{"id":201655,"date":"2025-05-10T09:04:05","date_gmt":"2025-05-10T01:04:05","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201655\/"},"modified":"2025-05-10T09:04:05","modified_gmt":"2025-05-10T01:04:05","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3%e8%b7%b3%e8%a1%a8%e5%8f%8a%e5%85%b6%e5%9c%a8redis%e4%b8%ad%e7%9a%84%e5%ba%94%e7%94%a8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201655\/","title":{"rendered":"\u6df1\u5165\u7406\u89e3\u8df3\u8868\u53ca\u5176\u5728Redis\u4e2d\u7684\u5e94\u7528"},"content":{"rendered":"

<\/b> <\/p>\n

\u6df1\u5165\u7406\u89e3\u8df3\u8868\u53ca\u5176\u5728Redis\u4e2d\u7684\u5e94\u7528<\/h1>\n

<\/i>\u6536\u85cf<\/span> <\/p>\n

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\u524d\u8a00<\/h2>\n

\u8df3\u8868\u53ef\u4ee5\u8fbe\u5230\u548c\u7ea2\u9ed1\u6811\u4e00\u6837\u7684\u65f6\u95f4\u590d\u6742\u5ea6 O(logN)\uff0c\u4e14\u5b9e\u73b0\u7b80\u5355\uff0cRedis \u4e2d\u7684\u6709\u5e8f\u96c6\u5408\u5bf9\u8c61\u7684\u5e95\u5c42\u6570\u636e\u7ed3\u6784\u5c31\u4f7f\u7528\u4e86\u8df3\u8868\u3002\u5176\u4f5c\u8005\u5a01\u5ec9\u00b7\u666e\u8bc4\u4ef7\uff1a\u8df3\u8dc3\u94fe\u8868\u662f\u5728\u5f88\u591a\u5e94\u7528\u4e2d\u6709\u53ef\u80fd\u66ff\u4ee3\u5e73\u8861\u6811\u7684\u4e00\u79cd\u6570\u636e\u7ed3\u6784\u3002\u672c\u7bc7\u6587\u7ae0\u5c06\u5bf9\u8df3\u8868\u7684\u5b9e\u73b0\u53ca\u5728Redis\u4e2d\u7684\u5e94\u7528\u8fdb\u884c\u5b66\u4e60\u3002<\/p>\n

\u4e00. \u8df3\u8868\u7684\u57fa\u7840\u6982\u5ff5<\/h2>\n

\u8df3\u8868\uff0c\u5373\u8df3\u8dc3\u94fe\u8868\uff08Skip List\uff09\uff0c\u662f\u57fa\u4e8e\u5e76\u8054\u7684\u94fe\u8868\u6570\u636e\u7ed3\u6784\uff0c\u64cd\u4f5c\u6548\u7387\u53ef\u4ee5\u8fbe\u5230O(logN)\uff0c\u5bf9\u5e76\u53d1\u53cb\u597d\uff0c\u8df3\u8868\u7684\u793a\u610f\u56fe\u5982\u4e0b\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\u8df3\u8868\u7684\u7279\u70b9\uff0c\u53ef\u4ee5\u6982\u62ec\u5982\u4e0b\u3002<\/p>\n

\u2022\u8df3\u8868\u662f\u591a\u5c42\uff08level\uff09\u94fe\u8868\u7ed3\u6784\uff1b<\/p>\n

\u2022\u8df3\u8868\u4e2d\u7684\u6bcf\u4e00\u5c42\u90fd\u662f\u4e00\u4e2a\u6709\u5e8f\u94fe\u8868\uff0c\u5e76\u4e14\u6309\u7167\u5143\u7d20\u5347\u5e8f\uff08\u9ed8\u8ba4\uff09\u6392\u5217\uff1b<\/p>\n

\u2022\u8df3\u8868\u4e2d\u7684\u5143\u7d20\u4f1a\u5728\u54ea\u4e00\u5c42\u51fa\u73b0\u662f\u968f\u673a\u51b3\u5b9a\u7684\uff0c\u4f46\u662f\u53ea\u8981\u5143\u7d20\u51fa\u73b0\u5728\u4e86\u7b2c k \u5c42\uff0c\u90a3\u4e48 k \u5c42\u4ee5\u4e0b\u7684\u94fe\u8868\u4e5f\u4f1a\u51fa\u73b0\u8fd9\u4e2a\u5143\u7d20\uff1b<\/p>\n

\u2022\u8df3\u8868\u7684\u5e95\u5c42\u7684\u94fe\u8868\u5305\u542b\u6240\u6709\u5143\u7d20\uff1b<\/p>\n

\u2022\u8df3\u8868\u5934\u8282\u70b9\u548c\u5c3e\u8282\u70b9\u4e0d\u5b58\u50a8\u5143\u7d20\uff0c\u4e14\u5934\u8282\u70b9\u548c\u5c3e\u8282\u70b9\u7684\u5c42\u6570\u5c31\u662f\u8df3\u8868\u7684\u6700\u5927\u5c42\u6570\uff1b<\/p>\n

\u2022\u8df3\u8868\u4e2d\u7684\u8282\u70b9\u5305\u542b\u4e24\u4e2a\u6307\u9488\uff0c\u4e00\u4e2a\u6307\u9488\u6307\u5411\u540c\u5c42\u94fe\u8868\u7684\u540e\u4e00\u8282\u70b9\uff0c\u4e00\u4e2a\u6307\u9488\u6307\u5411\u4e0b\u5c42\u94fe\u8868\u7684\u540c\u5143\u7d20\u8282\u70b9\u3002<\/p>\n

\u4ee5\u4e0a\u56fe\u4e2d\u7684\u8df3\u8868\u4e3a\u4f8b\uff0c\u5982\u679c\u8981\u67e5\u627e\u5143\u7d20 71\uff0c\u90a3\u4e48\u67e5\u627e\u6d41\u7a0b\u5982\u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\ufeff\ufeff\u4ece\u9876\u5c42\u94fe\u8868\u7684\u5934\u8282\u70b9\u5f00\u59cb\u67e5\u627e\uff0c\u67e5\u627e\u5230\u5143\u7d2071\u7684\u8282\u70b9\u65f6\uff0c\u4e00\u5171\u904d\u5386\u4e864\u4e2a\u8282\u70b9\uff0c\u4f46\u662f\u5982\u679c\u6309\u7167\u4f20\u7edf\u94fe\u8868\u7684\u65b9\u5f0f\uff08\u5373\u4ece\u8df3\u8868\u7684\u5e95\u5c42\u94fe\u8868\u7684\u5934\u8282\u70b9\u5f00\u59cb\u5411\u540e\u67e5\u627e\uff09\uff0c\u90a3\u4e48\u5c31\u9700\u8981\u904d\u53867\u4e2a\u8282\u70b9\uff0c\u6240\u4ee5\u8df3\u8868\u4ee5\u7a7a\u95f4\u6362\u65f6\u95f4\uff0c\u7f29\u77ed\u4e86\u64cd\u4f5c\u8df3\u8868\u6240\u9700\u8981\u82b1\u8d39\u7684\u65f6\u95f4\u3002\u8df3\u8dc3\u5217\u8868\u7684\u7b97\u6cd5\u6709\u540c\u5e73\u8861\u6811\u4e00\u6837\u7684\u6e10\u8fdb\u7684\u9884\u671f\u65f6\u95f4\u8fb9\u754c\uff0c\u5e76\u4e14\u66f4\u7b80\u5355\u3001\u66f4\u5feb\u901f\u548c\u4f7f\u7528\u66f4\u5c11\u7684\u7a7a\u95f4\u3002\u8fd9\u79cd\u6570\u636e\u7ed3\u6784\u662f\u7531William Pugh(\u97f3\u8bd1\u4e3a\u5a01\u5ec9\u00b7\u666e)\u53d1\u660e\u7684\uff0c\u6700\u65e9\u51fa\u73b0\u4e8e\u4ed6\u57281990\u5e74\u53d1\u8868\u7684\u8bba\u6587\u300aSkip Lists: A Probabilistic Alternative to Balanced Trees\u300b\u3002 \u8c37\u6b4c\u4e0a\u627e\u5230\u4e00\u7bc7\u4f5c\u8005\u5173\u4e8e\u8df3\u8868\u7684\u8bba\u6587\uff0c\u611f\u5174\u8da3\u5f3a\u70c8\u5efa\u8bae\u4e0b\u8f7d\u9605\u8bfb\uff1a<\/p>\n

\ufeffhttps:\/\/epaperpress.com\/sortsearch\/download\/skiplist.pdf\ufeff<\/p>\n

\u8df3\u8868\u5728\u52a8\u6001\u67e5\u627e\u8fc7\u7a0b\u4e2d\u4f7f\u7528\u4e86\u4e00\u79cd\u975e\u4e25\u683c\u7684\u5e73\u8861\u673a\u5236\u6765\u8ba9\u63d2\u5165\u548c\u5220\u9664\u90fd\u66f4\u52a0\u4fbf\u5229\u548c\u5feb\u6377\uff0c\u8fd9\u79cd\u975e\u4e25\u683c\u5e73\u8861\u662f\u57fa\u4e8e\u6982\u7387\u7684\uff0c\u800c\u4e0d\u662f\u5e73\u8861\u6811\u7684\u4e25\u683c\u5e73\u8861\u3002\u8bf4\u5230\u975e\u4e25\u683c\u5e73\u8861\uff0c\u9996\u5148\u60f3\u5230\u7684\u662f\u7ea2\u9ed1\u6811RbTree\uff0c\u5b83\u540c\u6837\u91c7\u7528\u975e\u4e25\u683c\u5e73\u8861\u6765\u907f\u514d\u50cfAVL\u90a3\u6837\u8c03\u6574\u6811\u7684\u7ed3\u6784\uff0c\u8fd9\u91cc\u5c31\u4e0d\u5c55\u5f00\u8bb2\u7ea2\u9ed1\u6811\u4e86\uff0c\u770b\u6765\u8df3\u8868\u4e5f\u662f\u7c7b\u4f3c\u7684\u8def\u5b50\uff0c\u4f46\u662f\u662f\u57fa\u4e8e\u6982\u7387\u5b9e\u73b0\u7684\u3002<\/p>\n

\u4e8c. \u8df3\u8868\u7684\u8282\u70b9<\/h2>\n

\u5df2\u77e5\u8df3\u8868\u4e2d\u7684\u8282\u70b9\uff0c\u9700\u8981\u6709\u6307\u5411\u5f53\u524d\u5c42\u94fe\u8868\u540e\u4e00\u8282\u70b9\u7684\u6307\u9488\uff0c\u548c\u6307\u5411\u4e0b\u5c42\u94fe\u8868\u7684\u540c\u5143\u7d20\u8282\u70b9\u7684\u6307\u9488\uff0c\u6240\u4ee5\u8df3\u8868\u4e2d\u7684\u8282\u70b9\uff0c\u5b9a\u4e49\u5982\u4e0b\u3002<\/p>\n

public class SkiplistNode {<\/span><\/p>\n

public int<\/span> data;<\/span>
public SkiplistNode next;<\/span>
public SkiplistNode down;<\/span>
public int<\/span> level;<\/span><\/p>\n

public SkiplistNode(<\/span>int<\/span> data,<\/span> int<\/span> level)<\/span> {<\/span>
this.data<\/span> =<\/span> data;<\/span>
this.level<\/span> =<\/span> level;<\/span>
}<\/span><\/p>\n

\u4e0a\u8ff0\u662f\u8df3\u8868\u4e2d\u7684\u8282\u70b9\u7684\u6700\u7b80\u5355\u7684\u5b9a\u4e49\u65b9\u5f0f\uff0c\u5b58\u50a8\u7684\u5143\u7d20 data \u4e3a\u6574\u6570\uff0c\u8282\u70b9\u4e4b\u95f4\u8fdb\u884c\u6bd4\u8f83\u65f6\u76f4\u63a5\u6bd4\u8f83\u5143\u7d20 data \u7684\u5927\u5c0f\u3002<\/p>\n

\u4e09. \u8df3\u8868\u7684\u521d\u59cb\u5316<\/h2>\n

\u8df3\u8868\u521d\u59cb\u5316\u65f6\uff0c\u5c06\u6bcf\u4e00\u5c42\u94fe\u8868\u7684\u5934\u5c3e\u8282\u70b9\u521b\u5efa\u51fa\u6765\u5e76\u4f7f\u7528\u96c6\u5408\u5c06\u5934\u5c3e\u8282\u70b9\u8fdb\u884c\u5b58\u50a8\uff0c\u5934\u5c3e\u8282\u70b9\u7684\u5c42\u6570\u968f\u673a\u6307\u5b9a\uff0c\u4e14\u5934\u5c3e\u8282\u70b9\u7684\u5c42\u6570\u5c31\u4ee3\u8868\u5f53\u524d\u8df3\u8868\u7684\u5c42\u6570\u3002\u521d\u59cb\u5316\u540e\uff0c\u8df3\u8868\u7ed3\u6784\u5982\u4e0b\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\ufeff\ufeff\u8df3\u8868\u521d\u59cb\u5316\u7684\u76f8\u5173\u4ee3\u7801\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

public LinkedListSkiplistNode><\/span> headNodes;<\/span>
public LinkedListSkiplistNode><\/span> tailNodes;<\/span><\/p>\n

public int<\/span> curLevel;<\/span><\/p>\n

public Random random;<\/span><\/p>\n

public Skiplist(<\/span>)<\/span> {<\/span>
random =<\/span> new Random(<\/span>)<\/span>;<\/span><\/p>\n

\/\/<\/span>headNodes\u7528\u4e8e\u5b58\u50a8\u6bcf\u4e00\u5c42\u7684\u5934\u8282\u70b9
headNodes =<\/span> new LinkedList<\/span>(<\/span>)<\/span>;<\/span>
\/\/<\/span>tailNodes\u7528\u4e8e\u5b58\u50a8\u6bcf\u4e00\u5c42\u7684\u5c3e\u8282\u70b9
tailNodes =<\/span> new LinkedList<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

\/\/<\/span>\u521d\u59cb\u5316\u8df3\u8868\u65f6\uff0c\u8df3\u8868\u7684\u5c42\u6570\u968f\u673a\u6307\u5b9a
curLevel =<\/span> getRandomLevel(<\/span>)<\/span>;<\/span>
\/\/<\/span>\u6307\u5b9a\u4e86\u8df3\u8868\u7684\u521d\u59cb\u7684\u968f\u673a\u5c42\u6570\u540e\uff0c\u5c31\u9700\u8981\u5c06\u6bcf\u4e00\u5c42\u7684\u5934\u8282\u70b9\u548c\u5c3e\u8282\u70b9\u521b\u5efa\u51fa\u6765\u5e76\u6784\u5efa\u597d\u5173\u7cfb
SkiplistNode head =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> 0<\/span>)<\/span>;<\/span>
SkiplistNode tail =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> 0<\/span>)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i curLevel;<\/span> i++<\/span>)<\/span> {<\/span>
head.next<\/span> =<\/span> tail;<\/span>
headNodes.addFirst<\/span>(<\/span>head)<\/span>;<\/span>
tailNodes.addFirst<\/span>(<\/span>tail)<\/span>;<\/span><\/p>\n

SkiplistNode headNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> head.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
SkiplistNode tailNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> tail.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
headNew.down<\/span> =<\/span> head;<\/span>
tailNew.down<\/span> =<\/span> tail;<\/span><\/p>\n

head =<\/span> headNew;<\/span>
tail =<\/span> tailNew;<\/span>
}<\/span>
}<\/span><\/span><\/span><\/span><\/p>\n

\u56db. \u8df3\u8868\u7684\u6dfb\u52a0\u65b9\u6cd5<\/h2>\n

\u6bcf\u4e00\u4e2a\u5143\u7d20\u6dfb\u52a0\u5230\u8df3\u8868\u4e2d\u65f6\uff0c\u9996\u5148\u9700\u8981\u968f\u673a\u6307\u5b9a\u8fd9\u4e2a\u5143\u7d20\u5728\u8df3\u8868\u4e2d\u7684\u5c42\u6570\uff0c\u5982\u679c\u968f\u673a\u6307\u5b9a\u7684\u5c42\u6570\u5927\u4e8e\u4e86\u8df3\u8868\u7684\u5c42\u6570\uff0c\u5219\u5728\u5c06\u5143\u7d20\u6dfb\u52a0\u5230\u8df3\u8868\u4e2d\u4e4b\u524d\uff0c\u8fd8\u9700\u8981\u6269\u5927\u8df3\u8868\u7684\u5c42\u6570\uff0c\u800c\u6269\u5927\u8df3\u8868\u7684\u5c42\u6570\u5c31\u662f\u5c06\u5934\u5c3e\u8282\u70b9\u7684\u5c42\u6570\u6269\u5927\u3002\u4e0b\u9762\u7ed9\u51fa\u9700\u8981\u6269\u5927\u8df3\u8868\u5c42\u6570\u7684\u4e00\u6b21\u6dfb\u52a0\u7684\u8fc7\u7a0b\u3002<\/p>\n

\u521d\u59cb\u72b6\u6001\u65f6\uff0c\u8df3\u8868\u7684\u5c42\u6570\u4e3a 2\uff0c\u5982\u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\u73b0\u5728\u8981\u5f80\u8df3\u8868\u4e2d\u6dfb\u52a0\u5143\u7d20 120\uff0c\u5e76\u4e14\u968f\u673a\u6307\u5b9a\u7684\u5c42\u6570\u4e3a 3\uff0c\u5927\u4e8e\u4e86\u5f53\u524d\u8df3\u8868\u7684\u5c42\u6570 2\uff0c\u6b64\u65f6\u9700\u8981\u5148\u6269\u5927\u8df3\u8868\u7684\u5c42\u6570\uff0c2\u5982 \u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\ufeff\ufeff\u5c06\u5143\u7d20 120 \u63d2\u5165\u5230\u8df3\u8868\u4e2d\u65f6\uff0c\u4ece\u9876\u5c42\u5f00\u59cb\uff0c\u9010\u5c42\u5411\u4e0b\u63d2\u5165\uff0c\u5982\u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<\/p>\n

<\/p>\n

\ufeff\ufeff\u8df3\u8868\u7684\u6dfb\u52a0\u65b9\u6cd5\u7684\u4ee3\u7801\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

public void add(<\/span>int<\/span> num)<\/span> {<\/span>
\/\/<\/span>\u83b7\u53d6\u672c\u6b21\u6dfb\u52a0\u7684\u503c\u7684\u5c42\u6570
int<\/span> level =<\/span> getRandomLevel(<\/span>)<\/span>;<\/span>
\/\/<\/span>\u5982\u679c\u672c\u6b21\u6dfb\u52a0\u7684\u503c\u7684\u5c42\u6570\u5927\u4e8e\u5f53\u524d\u8df3\u8868\u7684\u5c42\u6570
\/\/<\/span>\u5219\u9700\u8981\u5728\u6dfb\u52a0\u5f53\u524d\u503c\u524d\u5148\u5c06\u8df3\u8868\u5c42\u6570\u6269\u5145
if (<\/span>level ><\/span> curLevel)<\/span> {<\/span>
expanLevel(<\/span>level –<\/span> curLevel)<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>curNode\u8868\u793anum\u503c\u5728\u5f53\u524d\u5c42\u5bf9\u5e94\u7684\u8282\u70b9
SkiplistNode curNode =<\/span> new SkiplistNode(<\/span>num,<\/span> level)<\/span>;<\/span>
\/\/<\/span>preNode\u8868\u793acurNode\u5728\u5f53\u524d\u5c42\u7684\u524d\u4e00\u4e2a\u8282\u70b9
SkiplistNode preNode =<\/span> headNodes.get<\/span>(<\/span>curLevel –<\/span> level)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i level;<\/span> i++<\/span>)<\/span> {<\/span>
\/\/<\/span>\u4ece\u5f53\u524d\u5c42\u7684head\u8282\u70b9\u5f00\u59cb\u5411\u540e\u904d\u5386\uff0c\u76f4\u5230\u627e\u5230\u4e00\u4e2apreNode
\/\/<\/span>\u4f7f\u5f97preNode.data<\/span> num preNode.next<\/span>.data<\/span>
while (<\/span>preNode.next<\/span>.data<\/span> num)<\/span> {<\/span>
preNode =<\/span> preNode.next<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>\u5c06curNode\u63d2\u5165\u5230preNode\u548cpreNode.next<\/span>\u4e2d\u95f4
curNode.next<\/span> =<\/span> preNode.next<\/span>;<\/span>
preNode.next<\/span> =<\/span> curNode;<\/span><\/p>\n

\/\/<\/span>\u5982\u679c\u5f53\u524d\u5e76\u4e0d\u662f0\u5c42\uff0c\u5219\u7ee7\u7eed\u5411\u4e0b\u5c42\u6dfb\u52a0\u8282\u70b9
if (<\/span>curNode.level<\/span> ><\/span> 0<\/span>)<\/span> {<\/span>
SkiplistNode downNode =<\/span> new SkiplistNode(<\/span>num,<\/span> curNode.level<\/span> –<\/span> 1<\/span>)<\/span>;<\/span>
\/\/<\/span>curNode\u6307\u5411\u4e0b\u4e00\u5c42\u7684\u8282\u70b9
curNode.down<\/span> =<\/span> downNode;<\/span>
\/\/<\/span>curNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
curNode =<\/span> downNode;<\/span>
}<\/span>
\/\/<\/span>preNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
preNode =<\/span> preNode.down<\/span>;<\/span>
}<\/span>
}<\/span><\/p>\n

private void expanLevel(<\/span>int<\/span> expanCount)<\/span> {<\/span>
SkiplistNode head =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
SkiplistNode tail =<\/span> tailNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i expanCount;<\/span> i++<\/span>)<\/span> {<\/span>
SkiplistNode headNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> head.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
SkiplistNode tailNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> tail.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
headNew.down<\/span> =<\/span> head;<\/span>
tailNew.down<\/span> =<\/span> tail;<\/span><\/p>\n

head =<\/span> headNew;<\/span>
tail =<\/span> tailNew;<\/span><\/p>\n

headNodes.addFirst<\/span>(<\/span>head)<\/span>;<\/span>
tailNodes.addFirst<\/span>(<\/span>tail)<\/span>;<\/span>
}<\/span>
}<\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

\u4e94. \u8df3\u8868\u7684\u641c\u7d22\u65b9\u6cd5<\/h2>\n

\u5728\u8df3\u8868\u4e2d\u641c\u7d22\u4e00\u4e2a\u5143\u7d20\u65f6\uff0c\u9700\u8981\u4ece\u9876\u5c42\u5f00\u59cb\uff0c\u9010\u5c42\u5411\u4e0b\u641c\u7d22\u3002\u641c\u7d22\u65f6\u9075\u5faa\u5982\u4e0b\u89c4\u5219\u3002<\/p>\n

\u2022\u76ee\u6807\u503c\u5927\u4e8e\u5f53\u524d\u8282\u70b9\u7684\u540e\u4e00\u8282\u70b9\u503c\u65f6\uff0c\u7ee7\u7eed\u5728\u672c\u5c42\u94fe\u8868\u4e0a\u5411\u540e\u641c\u7d22\uff1b<\/p>\n

\u2022\u76ee\u6807\u503c\u5927\u4e8e\u5f53\u524d\u8282\u70b9\u503c\uff0c\u5c0f\u4e8e\u5f53\u524d\u8282\u70b9\u7684\u540e\u4e00\u8282\u70b9\u503c\u65f6\uff0c\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42\uff0c\u4ece\u4e0b\u5c42\u94fe\u8868\u7684\u540c\u8282\u70b9\u4f4d\u7f6e\u5411\u540e\u641c\u7d22\uff1b<\/p>\n

\u2022\u76ee\u6807\u503c\u7b49\u4e8e\u5f53\u524d\u8282\u70b9\u503c\uff0c\u641c\u7d22\u7ed3\u675f\u3002<\/p>\n

\u2022\u4e0b\u56fe\u662f\u4e00\u4e2a\u641c\u7d22\u8fc7\u7a0b\u7684\u793a\u610f\u56fe\u3002<\/p>\n<\/p>\n

<\/p>\n

\u2022\u8df3\u8868\u7684\u641c\u7d22\u7684\u4ee3\u7801\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

public boolean<\/span> search(<\/span>int<\/span> target)<\/span> {<\/span>
\/\/<\/span>\u4ece\u9876\u5c42\u5f00\u59cb\u5bfb\u627e\uff0ccurNode\u8868\u793a\u5f53\u524d\u904d\u5386\u5230\u7684\u8282\u70b9
SkiplistNode curNode =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
while (<\/span>curNode !=<\/span> null<\/span>)<\/span> {<\/span>
if (<\/span>curNode.next<\/span>.data<\/span> ==<\/span> target)<\/span> {<\/span>
\/\/<\/span>\u627e\u5230\u4e86\u76ee\u6807\u503c\u5bf9\u5e94\u7684\u8282\u70b9\uff0c\u6b64\u65f6\u8fd4\u56detrue
return true<\/span>;<\/span>
}<\/span> else if (<\/span>curNode.next<\/span>.data<\/span> ><\/span> target)<\/span> {<\/span>
\/\/<\/span>curNode\u7684\u540e\u4e00\u8282\u70b9\u503c\u5927\u4e8etarget
\/\/<\/span>\u8bf4\u660e\u76ee\u6807\u8282\u70b9\u5728curNode\u548ccurNode.next<\/span>\u4e4b\u95f4
\/\/<\/span>\u6b64\u65f6\u9700\u8981\u5411\u4e0b\u5c42\u5bfb\u627e
curNode =<\/span> curNode.down<\/span>;<\/span>
}<\/span> else {<\/span>
\/\/<\/span>curNode\u7684\u540e\u4e00\u8282\u70b9\u503c\u5c0f\u4e8etarget
\/\/<\/span>\u8bf4\u660e\u76ee\u6807\u8282\u70b9\u5728curNode\u7684\u540e\u4e00\u8282\u70b9\u7684\u540e\u9762
\/\/<\/span>\u6b64\u65f6\u5728\u672c\u5c42\u7ee7\u7eed\u5411\u540e\u5bfb\u627e
curNode =<\/span> curNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
return false<\/span>;<\/span>
}<\/span><\/p>\n

\u516d. \u8df3\u8868\u7684\u5220\u9664\u65b9\u6cd5<\/h2>\n

\u5f53\u5728\u8df3\u8868\u4e2d\u9700\u8981\u5220\u9664\u67d0\u4e00\u4e2a\u5143\u7d20\u65f6\uff0c\u5219\u9700\u8981\u5c06\u8fd9\u4e2a\u5143\u7d20\u5728\u6240\u6709\u5c42\u7684\u8282\u70b9\u90fd\u5220\u9664\uff0c\u5177\u4f53\u7684\u5220\u9664\u89c4\u5219\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

\u2022\u9996\u5148\u6309\u7167\u8df3\u8868\u7684\u641c\u7d22\u7684\u65b9\u5f0f\uff0c\u641c\u7d22\u5f85\u5220\u9664\u8282\u70b9\uff0c\u5982\u679c\u80fd\u591f\u641c\u7d22\u5230\uff0c\u6b64\u65f6\u641c\u7d22\u5230\u7684\u5f85\u5220\u9664\u8282\u70b9\u4f4d\u4e8e\u8be5\u8282\u70b9\u5c42\u6570\u7684\u6700\u9ad8\u5c42\uff1b<\/p>\n

\u2022\u4ece\u5f85\u5220\u9664\u8282\u70b9\u7684\u6700\u9ad8\u5c42\u5f80\u4e0b\uff0c\u5c06\u6bcf\u4e00\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9\u90fd\u5220\u9664\u6389\uff0c\u5220\u9664\u65b9\u5f0f\u5c31\u662f\u8ba9\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9\u76f4\u63a5\u6307\u5411\u5f85\u5220\u9664\u8282\u70b9\u7684\u540e\u4e00\u8282\u70b9\u3002<\/p>\n

\u2022\u4e0b\u56fe\u662f\u4e00\u4e2a\u5220\u9664\u8fc7\u7a0b\u7684\u793a\u610f\u56fe\u3002<\/p>\n<\/p>\n

<\/p>\n

\u2022\u8df3\u8868\u7684\u5220\u9664\u7684\u4ee3\u7801\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

public boolean<\/span> erase(<\/span>int<\/span> num)<\/span> {<\/span>
\/\/<\/span>\u5220\u9664\u8282\u70b9\u7684\u904d\u5386\u8fc7\u7a0b\u4e0e\u5bfb\u627e\u8282\u70b9\u7684\u904d\u5386\u8fc7\u7a0b\u662f\u76f8\u540c\u7684
\/\/<\/span>\u4e0d\u8fc7\u5728\u5220\u9664\u8282\u70b9\u65f6\u5982\u679c\u627e\u5230\u76ee\u6807\u8282\u70b9\uff0c\u5219\u9700\u8981\u6267\u884c\u8282\u70b9\u5220\u9664\u7684\u64cd\u4f5c
SkiplistNode curNode =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
while (<\/span>curNode !=<\/span> null<\/span>)<\/span> {<\/span>
if (<\/span>curNode.next<\/span>.data<\/span> ==<\/span> num)<\/span> {<\/span>
\/\/<\/span>preDeleteNode\u8868\u793a\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9
SkiplistNode preDeleteNode =<\/span> curNode;<\/span>
while (<\/span>true<\/span>)<\/span> {<\/span>
\/\/<\/span>\u5220\u9664\u5f53\u524d\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9\uff0c\u5c31\u662f\u8ba9\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9\u6307\u5411\u5f85\u5220\u9664\u8282\u70b9\u7684\u540e\u4e00\u8282\u70b9
preDeleteNode.next<\/span> =<\/span> curNode.next<\/span>.next<\/span>;<\/span>
\/\/<\/span>\u5f53\u524d\u5c42\u5220\u9664\u5b8c\u540e\uff0c\u9700\u8981\u7ee7\u7eed\u5220\u9664\u4e0b\u4e00\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9
\/\/<\/span>\u8fd9\u91cc\u8ba9preDeleteNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
\/\/<\/span>\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42\u540e\uff0cpreDeleteNode\u5c31\u4e0d\u4e00\u5b9a\u662f\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9\u4e86
preDeleteNode =<\/span> preDeleteNode.down<\/span>;<\/span><\/p>\n

\/\/<\/span>\u5982\u679cpreDeleteNode\u4e3anull\uff0c\u8bf4\u660e\u5df2\u7ecf\u5c06\u5e95\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9\u5220\u9664\u4e86
\/\/<\/span>\u6b64\u65f6\u5c31\u7ed3\u675f\u5220\u9664\u6d41\u7a0b\uff0c\u5e76\u8fd4\u56detrue
if (<\/span>preDeleteNode ==<\/span> null<\/span>)<\/span> {<\/span>
return true<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>preDeleteNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42\u540e\uff0c\u9700\u8981\u7ee7\u7eed\u4ece\u5f53\u524d\u4f4d\u7f6e\u5411\u540e\u904d\u5386
\/\/<\/span>\u76f4\u5230\u627e\u5230\u4e00\u4e2apreDeleteNode\uff0c\u4f7f\u5f97preDeleteNode.next<\/span>\u7684\u503c\u7b49\u4e8e\u76ee\u6807\u503c
\/\/<\/span>\u6b64\u65f6preDeleteNode\u5c31\u53c8\u53d8\u6210\u4e86\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9
while (<\/span>preDeleteNode.next<\/span>.data<\/span> !=<\/span> num)<\/span> {<\/span>
preDeleteNode =<\/span> preDeleteNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
}<\/span> else if (<\/span>curNode.next<\/span>.data<\/span> ><\/span> num)<\/span> {<\/span>
curNode =<\/span> curNode.down<\/span>;<\/span>
}<\/span> else {<\/span>
curNode =<\/span> curNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
return false<\/span>;<\/span>
}<\/span><\/p>\n

\u4e03. \u8df3\u8868\u5b8c\u6574\u4ee3\u7801<\/h2>\n

\u8df3\u8868\u5b8c\u6574\u4ee3\u7801\u5982\u4e0b\u6240\u793a\u3002<\/p>\n

public class Skiplist {<\/span><\/p>\n

public LinkedListSkiplistNode><\/span> headNodes;<\/span>
public LinkedListSkiplistNode><\/span> tailNodes;<\/span><\/p>\n

public int<\/span> curLevel;<\/span><\/p>\n

public Random random;<\/span><\/p>\n

public Skiplist(<\/span>)<\/span> {<\/span>
random =<\/span> new Random(<\/span>)<\/span>;<\/span><\/p>\n

\/\/<\/span>headNodes\u7528\u4e8e\u5b58\u50a8\u6bcf\u4e00\u5c42\u7684\u5934\u8282\u70b9
headNodes =<\/span> new LinkedList<\/span>(<\/span>)<\/span>;<\/span>
\/\/<\/span>tailNodes\u7528\u4e8e\u5b58\u50a8\u6bcf\u4e00\u5c42\u7684\u5c3e\u8282\u70b9
tailNodes =<\/span> new LinkedList<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

\/\/<\/span>\u521d\u59cb\u5316\u8df3\u8868\u65f6\uff0c\u8df3\u8868\u7684\u5c42\u6570\u968f\u673a\u6307\u5b9a
curLevel =<\/span> getRandomLevel(<\/span>)<\/span>;<\/span>
\/\/<\/span>\u6307\u5b9a\u4e86\u8df3\u8868\u7684\u521d\u59cb\u7684\u968f\u673a\u5c42\u6570\u540e\uff0c\u5c31\u9700\u8981\u5c06\u6bcf\u4e00\u5c42\u7684\u5934\u8282\u70b9\u548c\u5c3e\u8282\u70b9\u521b\u5efa\u51fa\u6765\u5e76\u6784\u5efa\u597d\u5173\u7cfb
SkiplistNode head =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> 0<\/span>)<\/span>;<\/span>
SkiplistNode tail =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> 0<\/span>)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i curLevel;<\/span> i++<\/span>)<\/span> {<\/span>
head.next<\/span> =<\/span> tail;<\/span>
headNodes.addFirst<\/span>(<\/span>head)<\/span>;<\/span>
tailNodes.addFirst<\/span>(<\/span>tail)<\/span>;<\/span><\/p>\n

SkiplistNode headNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> head.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
SkiplistNode tailNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> tail.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
headNew.down<\/span> =<\/span> head;<\/span>
tailNew.down<\/span> =<\/span> tail;<\/span><\/p>\n

head =<\/span> headNew;<\/span>
tail =<\/span> tailNew;<\/span>
}<\/span>
}<\/span><\/p>\n

public boolean<\/span> search(<\/span>int<\/span> target)<\/span> {<\/span>
\/\/<\/span>\u4ece\u9876\u5c42\u5f00\u59cb\u5bfb\u627e\uff0ccurNode\u8868\u793a\u5f53\u524d\u904d\u5386\u5230\u7684\u8282\u70b9
SkiplistNode curNode =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
while (<\/span>curNode !=<\/span> null<\/span>)<\/span> {<\/span>
if (<\/span>curNode.next<\/span>.data<\/span> ==<\/span> target)<\/span> {<\/span>
\/\/<\/span>\u627e\u5230\u4e86\u76ee\u6807\u503c\u5bf9\u5e94\u7684\u8282\u70b9\uff0c\u6b64\u65f6\u8fd4\u56detrue
return true<\/span>;<\/span>
}<\/span> else if (<\/span>curNode.next<\/span>.data<\/span> ><\/span> target)<\/span> {<\/span>
\/\/<\/span>curNode\u7684\u540e\u4e00\u8282\u70b9\u503c\u5927\u4e8etarget
\/\/<\/span>\u8bf4\u660e\u76ee\u6807\u8282\u70b9\u5728curNode\u548ccurNode.next<\/span>\u4e4b\u95f4
\/\/<\/span>\u6b64\u65f6\u9700\u8981\u5411\u4e0b\u5c42\u5bfb\u627e
curNode =<\/span> curNode.down<\/span>;<\/span>
}<\/span> else {<\/span>
\/\/<\/span>curNode\u7684\u540e\u4e00\u8282\u70b9\u503c\u5c0f\u4e8etarget
\/\/<\/span>\u8bf4\u660e\u76ee\u6807\u8282\u70b9\u5728curNode\u7684\u540e\u4e00\u8282\u70b9\u7684\u540e\u9762
\/\/<\/span>\u6b64\u65f6\u5728\u672c\u5c42\u7ee7\u7eed\u5411\u540e\u5bfb\u627e
curNode =<\/span> curNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
return false<\/span>;<\/span>
}<\/span><\/p>\n

public void add(<\/span>int<\/span> num)<\/span> {<\/span>
\/\/<\/span>\u83b7\u53d6\u672c\u6b21\u6dfb\u52a0\u7684\u503c\u7684\u5c42\u6570
int<\/span> level =<\/span> getRandomLevel(<\/span>)<\/span>;<\/span>
\/\/<\/span>\u5982\u679c\u672c\u6b21\u6dfb\u52a0\u7684\u503c\u7684\u5c42\u6570\u5927\u4e8e\u5f53\u524d\u8df3\u8868\u7684\u5c42\u6570
\/\/<\/span>\u5219\u9700\u8981\u5728\u6dfb\u52a0\u5f53\u524d\u503c\u524d\u5148\u5c06\u8df3\u8868\u5c42\u6570\u6269\u5145
if (<\/span>level ><\/span> curLevel)<\/span> {<\/span>
expanLevel(<\/span>level –<\/span> curLevel)<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>curNode\u8868\u793anum\u503c\u5728\u5f53\u524d\u5c42\u5bf9\u5e94\u7684\u8282\u70b9
SkiplistNode curNode =<\/span> new SkiplistNode(<\/span>num,<\/span> level)<\/span>;<\/span>
\/\/<\/span>preNode\u8868\u793acurNode\u5728\u5f53\u524d\u5c42\u7684\u524d\u4e00\u4e2a\u8282\u70b9
SkiplistNode preNode =<\/span> headNodes.get<\/span>(<\/span>curLevel –<\/span> level)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i level;<\/span> i++<\/span>)<\/span> {<\/span>
\/\/<\/span>\u4ece\u5f53\u524d\u5c42\u7684head\u8282\u70b9\u5f00\u59cb\u5411\u540e\u904d\u5386\uff0c\u76f4\u5230\u627e\u5230\u4e00\u4e2apreNode
\/\/<\/span>\u4f7f\u5f97preNode.data<\/span> num preNode.next<\/span>.data<\/span>
while (<\/span>preNode.next<\/span>.data<\/span> num)<\/span> {<\/span>
preNode =<\/span> preNode.next<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>\u5c06curNode\u63d2\u5165\u5230preNode\u548cpreNode.next<\/span>\u4e2d\u95f4
curNode.next<\/span> =<\/span> preNode.next<\/span>;<\/span>
preNode.next<\/span> =<\/span> curNode;<\/span><\/p>\n

\/\/<\/span>\u5982\u679c\u5f53\u524d\u5e76\u4e0d\u662f0\u5c42\uff0c\u5219\u7ee7\u7eed\u5411\u4e0b\u5c42\u6dfb\u52a0\u8282\u70b9
if (<\/span>curNode.level<\/span> ><\/span> 0<\/span>)<\/span> {<\/span>
SkiplistNode downNode =<\/span> new SkiplistNode(<\/span>num,<\/span> curNode.level<\/span> –<\/span> 1<\/span>)<\/span>;<\/span>
\/\/<\/span>curNode\u6307\u5411\u4e0b\u4e00\u5c42\u7684\u8282\u70b9
curNode.down<\/span> =<\/span> downNode;<\/span>
\/\/<\/span>curNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
curNode =<\/span> downNode;<\/span>
}<\/span>
\/\/<\/span>preNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
preNode =<\/span> preNode.down<\/span>;<\/span>
}<\/span>
}<\/span><\/p>\n

public boolean<\/span> erase(<\/span>int<\/span> num)<\/span> {<\/span>
\/\/<\/span>\u5220\u9664\u8282\u70b9\u7684\u904d\u5386\u8fc7\u7a0b\u4e0e\u5bfb\u627e\u8282\u70b9\u7684\u904d\u5386\u8fc7\u7a0b\u662f\u76f8\u540c\u7684
\/\/<\/span>\u4e0d\u8fc7\u5728\u5220\u9664\u8282\u70b9\u65f6\u5982\u679c\u627e\u5230\u76ee\u6807\u8282\u70b9\uff0c\u5219\u9700\u8981\u6267\u884c\u8282\u70b9\u5220\u9664\u7684\u64cd\u4f5c
SkiplistNode curNode =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
while (<\/span>curNode !=<\/span> null<\/span>)<\/span> {<\/span>
if (<\/span>curNode.next<\/span>.data<\/span> ==<\/span> num)<\/span> {<\/span>
\/\/<\/span>preDeleteNode\u8868\u793a\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9
SkiplistNode preDeleteNode =<\/span> curNode;<\/span>
while (<\/span>true<\/span>)<\/span> {<\/span>
\/\/<\/span>\u5220\u9664\u5f53\u524d\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9\uff0c\u5c31\u662f\u8ba9\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9\u6307\u5411\u5f85\u5220\u9664\u8282\u70b9\u7684\u540e\u4e00\u8282\u70b9
preDeleteNode.next<\/span> =<\/span> curNode.next<\/span>.next<\/span>;<\/span>
\/\/<\/span>\u5f53\u524d\u5c42\u5220\u9664\u5b8c\u540e\uff0c\u9700\u8981\u7ee7\u7eed\u5220\u9664\u4e0b\u4e00\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9
\/\/<\/span>\u8fd9\u91cc\u8ba9preDeleteNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42
\/\/<\/span>\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42\u540e\uff0cpreDeleteNode\u5c31\u4e0d\u4e00\u5b9a\u662f\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9\u4e86
preDeleteNode =<\/span> preDeleteNode.down<\/span>;<\/span><\/p>\n

\/\/<\/span>\u5982\u679cpreDeleteNode\u4e3anull\uff0c\u8bf4\u660e\u5df2\u7ecf\u5c06\u5e95\u5c42\u7684\u5f85\u5220\u9664\u8282\u70b9\u5220\u9664\u4e86
\/\/<\/span>\u6b64\u65f6\u5c31\u7ed3\u675f\u5220\u9664\u6d41\u7a0b\uff0c\u5e76\u8fd4\u56detrue
if (<\/span>preDeleteNode ==<\/span> null<\/span>)<\/span> {<\/span>
return true<\/span>;<\/span>
}<\/span><\/p>\n

\/\/<\/span>preDeleteNode\u5411\u4e0b\u79fb\u52a8\u4e00\u5c42\u540e\uff0c\u9700\u8981\u7ee7\u7eed\u4ece\u5f53\u524d\u4f4d\u7f6e\u5411\u540e\u904d\u5386
\/\/<\/span>\u76f4\u5230\u627e\u5230\u4e00\u4e2apreDeleteNode\uff0c\u4f7f\u5f97preDeleteNode.next<\/span>\u7684\u503c\u7b49\u4e8e\u76ee\u6807\u503c
\/\/<\/span>\u6b64\u65f6preDeleteNode\u5c31\u53c8\u53d8\u6210\u4e86\u5f85\u5220\u9664\u8282\u70b9\u7684\u524d\u4e00\u8282\u70b9
while (<\/span>preDeleteNode.next<\/span>.data<\/span> !=<\/span> num)<\/span> {<\/span>
preDeleteNode =<\/span> preDeleteNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
}<\/span> else if (<\/span>curNode.next<\/span>.data<\/span> ><\/span> num)<\/span> {<\/span>
curNode =<\/span> curNode.down<\/span>;<\/span>
}<\/span> else {<\/span>
curNode =<\/span> curNode.next<\/span>;<\/span>
}<\/span>
}<\/span>
return false<\/span>;<\/span>
}<\/span><\/p>\n

private void expanLevel(<\/span>int<\/span> expanCount)<\/span> {<\/span>
SkiplistNode head =<\/span> headNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
SkiplistNode tail =<\/span> tailNodes.getFirst<\/span>(<\/span>)<\/span>;<\/span>
for (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i expanCount;<\/span> i++<\/span>)<\/span> {<\/span>
SkiplistNode headNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MIN_VALUE<\/span>,<\/span> head.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
SkiplistNode tailNew =<\/span> new SkiplistNode(<\/span>Integer<\/span>.MAX_VALUE<\/span>,<\/span> tail.level<\/span> +<\/span> 1<\/span>)<\/span>;<\/span>
headNew.down<\/span> =<\/span> head;<\/span>
tailNew.down<\/span> =<\/span> tail;<\/span><\/p>\n

head =<\/span> headNew;<\/span>
tail =<\/span> tailNew;<\/span><\/p>\n

headNodes.addFirst<\/span>(<\/span>head)<\/span>;<\/span>
tailNodes.addFirst<\/span>(<\/span>tail)<\/span>;<\/span>
}<\/span>
}<\/span><\/p>\n

private int<\/span> getRandomLevel(<\/span>)<\/span> {<\/span>
int<\/span> level =<\/span> 0<\/span>;<\/span>
while (<\/span>random.nextInt<\/span>(<\/span>2<\/span>)<\/span> ><\/span> 1<\/span>)<\/span> {<\/span>
level++<\/span>;<\/span>
}<\/span>
return level;<\/span>
}<\/span><\/p>\n

}<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

\u516b. \u8df3\u8868\u5728Redis\u4e2d\u7684\u5e94\u7528<\/h2>\n

ZSet\u7ed3\u6784\u540c\u65f6\u5305\u542b\u4e00\u4e2a\u5b57\u5178\u548c\u4e00\u4e2a\u8df3\u8dc3\u8868\uff0c\u8df3\u8dc3\u8868\u6309score\u4ece\u5c0f\u5230\u5927\u4fdd\u5b58\u6240\u6709\u96c6\u5408\u5143\u7d20\u3002\u5b57\u5178\u4fdd\u5b58\u7740\u4ecemember\u5230score\u7684\u6620\u5c04\u3002\u8fd9\u4e24\u79cd\u7ed3\u6784\u901a\u8fc7\u6307\u9488\u5171\u4eab\u76f8\u540c\u5143\u7d20\u7684member\u548cscore\uff0c\u4e0d\u4f1a\u6d6a\u8d39\u989d\u5916\u5185\u5b58\u3002<\/p>\n

typedef struct zset {<\/span>
dict *<\/span>dict;<\/span>
zskiplist *<\/span>zsl;<\/span>
}<\/span> zset;<\/span><\/p>\n

ZSet\u4e2d\u7684\u5b57\u5178\u548c\u8df3\u8868\u5e03\u5c40\uff1a<\/p>\n<\/p>\n

<\/p>\n

1.ZSet\u4e2d\u8df3\u8868\u7684\u5b9e\u73b0\u7ec6\u8282<\/h2>\n

\u968f\u673a\u5c42\u6570\u7684\u5b9e\u73b0\u539f\u7406\uff1a<\/p>\n

\u8df3\u8868\u662f\u4e00\u4e2a\u6982\u7387\u578b\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5143\u7d20\u7684\u63d2\u5165\u5c42\u6570\u662f\u968f\u673a\u6307\u5b9a\u7684\u3002Willam Pugh\u5728\u8bba\u6587\u4e2d\u63cf\u8ff0\u4e86\u5b83\u7684\u8ba1\u7b97\u8fc7\u7a0b\u5982\u4e0b\uff1a\u6307\u5b9a\u8282\u70b9\u6700\u5927\u5c42\u6570 MaxLevel\uff0c\u6307\u5b9a\u6982\u7387 p\uff0c \u9ed8\u8ba4\u5c42\u6570 lvl \u4e3a1\uff1b<\/p>\n

\u751f\u6210\u4e00\u4e2a0~1\u7684\u968f\u673a\u6570r\uff0c\u82e5r<\/p>\n<\/p>\n

\u91cd\u590d\u7b2c 2 \u6b65\uff0c\u76f4\u81f3\u751f\u6210\u7684r >p \u4e3a\u6b62\uff0c\u6b64\u65f6\u7684 lvl \u5c31\u662f\u8981\u63d2\u5165\u7684\u5c42\u6570\u3002<\/p>\n

\u8bba\u6587\u4e2d\u751f\u6210\u968f\u673a\u5c42\u6570\u7684\u4f2a\u7801\uff1a<\/p>\n<\/p>\n

<\/p>\n

\u5728Redis\u4e2d\u5bf9\u8df3\u8868\u7684\u5b9e\u73b0\u57fa\u672c\u4e0a\u4e5f\u662f\u9075\u5faa\u8fd9\u4e2a\u601d\u60f3\u7684\uff0c\u53ea\u4e0d\u8fc7\u6709\u5fae\u5c0f\u5dee\u5f02\uff0c\u770b\u4e0bRedis\u5173\u4e8e\u8df3\u8868\u5c42\u6570\u7684\u968f\u673a\u6e90\u7801src\/z_set.c\uff1a<\/p>\n

\/* Returns a random level for the new skiplist node we are going to create.<\/span>
* The return value of this function is between 1 and ZSKIPLIST_MAXLEVEL<\/span>
* (both inclusive), with a powerlaw-alike distribution where higher<\/span>
* levels are less likely to be returned. *\/<\/span>
int<\/span> zslRandomLevel(<\/span>void)<\/span> {<\/span>
int<\/span> level =<\/span> 1<\/span>;<\/span>
while (<\/span>(<\/span>random(<\/span>)<\/span>&<\/span>0xFFFF<\/span>)<\/span> (<\/span>ZSKIPLIST_P *<\/span> 0xFFFF<\/span>)<\/span>)<\/span>
level +=<\/span> 1<\/span>;<\/span>
return (<\/span>levelZSKIPLIST_MAXLEVEL)<\/span> ? <\/span>level :<\/span> ZSKIPLIST_MAXLEVEL;<\/span>
}<\/span><\/span><\/span><\/p>\n

\u5176\u4e2d\u4e24\u4e2a\u5b8f\u7684\u5b9a\u4e49\u5728redis.h\u4e2d\uff1a<\/p>\n

#define ZSKIPLIST_MAXLEVEL 32<\/span> \/* Should be enough for 2^32 elements *\/<\/span>
#define ZSKIPLIST_P 0.25<\/span> \/* Skiplist P = 1\/4 *\/<\/span><\/p>\n

\u53ef\u4ee5\u770b\u5230while\u4e2d\u7684\uff1a<\/p>\n

(<\/span>random(<\/span>)<\/span>&<\/span>0xFFFF<\/span>)<\/span> (<\/span>ZSKIPLIST_P*<\/span>0xFFFF<\/span>)<\/span><\/span><\/p>\n

\u7b2c\u4e00\u773c\u770b\u5230\u8fd9\u4e2a\u516c\u5f0f\uff0c\u56e0\u4e3a\u6d89\u53ca\u4f4d\u8fd0\u7b97\u6709\u4e9b\u8be7\u5f02\uff0c\u9700\u8981\u7814\u7a76\u4e00\u4e0bAntirez\u4e3a\u4ec0\u4e48\u4f7f\u7528\u4f4d\u8fd0\u7b97\u6765\u8fd9\u4e48\u5199\uff1f<\/p>\n

\u6700\u5f00\u59cb\u7684\u731c\u6d4b\u662frandom()\u8fd4\u56de\u7684\u662f\u6d6e\u70b9\u6570[0-1]\uff0c\u4e8e\u662f\u4e4e\u5728\u7ebf\u627e\u4e86\u4e2a\u6d6e\u70b9\u6570\u8f6c\u4e8c\u8fdb\u5236\u7684\u5de5\u5177\uff0c\u8f93\u51650.5\u770b\u4e86\u4e0b\u7ed3\u679c\uff1a<\/p>\n<\/p>\n

<\/p>\n

\u53ef\u4ee5\u770b\u52300.5\u768432bit\u8f6c\u636216\u8fdb\u5236\u7ed3\u679c\u4e3a0x3f000000\uff0c\u5982\u679c\u4e0e0xFFFF\u505a\u4e0e\u8fd0\u7b97\u7ed3\u679c\u8fd8\u662f0\uff0c\u4e0d\u7b26\u5408\u9884\u671f\u3002<\/p>\n

\u5b9e\u9645\u5e94\u7528\u65f6\u5bf9\u4e8e\u968f\u673a\u5c42\u6570\u7684\u5b9e\u73b0\u5e76\u4e0d\u7edf\u4e00\uff0c\u91cd\u8981\u7684\u662f\u968f\u673a\u6570\u7684\u751f\u6210\uff0c\u5728LevelDB\u4e2d\u5bf9\u8df3\u8868\u5c42\u6570\u7684\u751f\u6210\u4ee3\u7801\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n

template typename Key,<\/span> typename Value><\/span>
int<\/span> SkipListKey,<\/span> Value><\/span>::<\/span>randomLevel(<\/span>)<\/span> {<\/span><\/p>\n

static const unsigned<\/span> int<\/span> kBranching =<\/span> 4<\/span>;<\/span>
int<\/span> height =<\/span> 1<\/span>;<\/span>
while (<\/span>height kMaxLevel &&<\/span> (<\/span>(<\/span>::<\/span>Next(<\/span>rnd_)<\/span> %<\/span> kBranching)<\/span> ==<\/span> 0<\/span>)<\/span>)<\/span> {<\/span>
height++<\/span>;<\/span>
}<\/span>
assert(<\/span>height ><\/span> 0<\/span>)<\/span>;<\/span>
assert(<\/span>height kMaxLevel)<\/span>;<\/span>
return height;<\/span>
}<\/span><\/p>\n

uint32_t Next(<\/span> uint32_t&<\/span> seed)<\/span> {<\/span>
seed =<\/span> seed &<\/span> 0x7fffffff<\/span>u;<\/span><\/p>\n

if (<\/span>seed ==<\/span> 0<\/span> ||<\/span> seed ==<\/span> 2147483647<\/span>L)<\/span> {<\/span>
seed =<\/span> 1<\/span>;<\/span>
}<\/span>
static const uint32_t M =<\/span> 2147483647<\/span>L;<\/span>
static const uint64_t A =<\/span> 16807<\/span>;<\/span>
uint64_t product =<\/span> seed *<\/span> A;<\/span>
seed =<\/span> static_castuint32_t><\/span>(<\/span>(<\/span>product >><\/span> 31<\/span>)<\/span> +<\/span> (<\/span>product &<\/span> M)<\/span>)<\/span>;<\/span>
if (<\/span>seed ><\/span> M)<\/span> {<\/span>
seed -=<\/span> M;<\/span>
}<\/span>
return seed;<\/span>
}<\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

\u53ef\u4ee5\u770b\u5230leveldb\u4f7f\u7528\u968f\u673a\u6570\u4e0ekBranching\u53d6\u6a21\uff0c\u5982\u679c\u503c\u4e3a0\u5c31\u589e\u52a0\u4e00\u5c42\uff0c\u8fd9\u6837\u867d\u7136\u6ca1\u6709\u4f7f\u7528\u6d6e\u70b9\u6570\uff0c\u4f46\u662f\u4e5f\u5b9e\u73b0\u4e86\u6982\u7387\u5e73\u8861\u3002<\/p>\n

2.\u8df3\u8868\u7ed3\u70b9\u7684\u5e73\u5747\u5c42\u6570<\/h2>\n

\u6211\u4eec\u5f88\u5bb9\u6613\u770b\u51fa\uff0c\u4ea7\u751f\u8d8a\u9ad8\u7684\u8282\u70b9\u5c42\u6570\u51fa\u73b0\u6982\u7387\u8d8a\u4f4e\uff0c\u65e0\u8bba\u5982\u4f55\u5c42\u6570\u603b\u662f\u6ee1\u8db3\u5e42\u6b21\u5b9a\u5f8b\u8d8a\u5927\u7684\u6570\u51fa\u73b0\u7684\u6982\u7387\u8d8a\u5c0f\u3002<\/p>\n

\n

\u5982\u679c\u67d0\u4ef6\u4e8b\u7684\u53d1\u751f\u9891\u7387\u548c\u5b83\u7684\u67d0\u4e2a\u5c5e\u6027\u6210\u5e42\u5173\u7cfb\uff0c\u90a3\u4e48\u8fd9\u4e2a\u9891\u7387\u5c31\u53ef\u4ee5\u79f0\u4e4b\u4e3a\u7b26\u5408\u5e42\u6b21\u5b9a\u5f8b\u3002<\/p>\n

\u5e42\u6b21\u5b9a\u5f8b\u7684\u8868\u73b0\u662f\u5c11\u6570\u51e0\u4e2a\u4e8b\u4ef6\u7684\u53d1\u751f\u9891\u7387\u5360\u4e86\u6574\u4e2a\u53d1\u751f\u9891\u7387\u7684\u5927\u90e8\u5206\uff0c \u800c\u5176\u4f59\u7684\u5927\u591a\u6570\u4e8b\u4ef6\u53ea\u5360\u6574\u4e2a\u53d1\u751f\u9891\u7387\u7684\u4e00\u4e2a\u5c0f\u90e8\u5206\u3002<\/p>\n<\/blockquote>\n

\u5e42\u6b21\u5b9a\u5f8b\u5e94\u7528\u5230\u8df3\u8868\u7684\u968f\u673a\u5c42\u6570\u6765\u8bf4\u5c31\u662f\u5927\u90e8\u5206\u7684\u8282\u70b9\u5c42\u6570\u90fd\u662f\u9ec4\u8272\u90e8\u5206\uff0c\u53ea\u6709\u5c11\u6570\u662f\u7eff\u8272\u90e8\u5206\uff0c\u5e76\u4e14\u6982\u7387\u5f88\u4f4e\u3002<\/p>\n

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\u603b\u7ed3<\/h2>\n

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