{"id":275148,"date":"2024-05-16T14:20:27","date_gmt":"2024-05-16T06:20:27","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/275148.html"},"modified":"2024-05-16T14:20:48","modified_gmt":"2024-05-16T06:20:48","slug":"c-%e8%af%ad%e8%a8%80%e9%a1%b9%e7%9b%ae%e6%80%8e%e4%b9%88%e5%ae%9e%e7%8e%b0%e8%b7%b3%e8%a1%a8-skiplist","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/275148.html","title":{"rendered":"C \u8bed\u8a00\u9879\u76ee\u600e\u4e48\u5b9e\u73b0\u8df3\u8868 SkipList"},"content":{"rendered":"

\"C<\/p>\n

C \u8bed\u8a00\u4e2d\u5b9e\u73b0\u8df3\u8868\uff08SkipList\uff09\u7684\u8fc7\u7a0b\u4e3b\u8981\u5305\u62ec\uff1a\u521b\u5efa\u8282\u70b9\u7ed3\u6784<\/strong>\u3001\u521d\u59cb\u5316\u8df3\u8868<\/strong>\u3001\u63d2\u5165\u8282\u70b9<\/strong>\u3001\u67e5\u627e\u8282\u70b9<\/strong>\u3001\u5220\u9664\u8282\u70b9<\/strong>\u3001\u91ca\u653e\u8df3\u8868<\/strong>\u3002\u8df3\u8868\u662f\u4e00\u79cd\u9ad8\u6548\u7684\u52a8\u6001\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u901a\u8fc7\u5728\u6807\u51c6\u7684\u6709\u5e8f\u94fe\u8868\u4e0a\u589e\u52a0\u591a\u7ea7\u7d22\u5f15\u6765\u5b9e\u73b0\u5feb\u901f\u7684\u67e5\u627e\u6548\u7387\uff0c\u901a\u5e38\u80fd\u5728\u5bf9\u6570\u65f6\u95f4\u590d\u6742\u5ea6\u5185\u5b8c\u6210\u67e5\u627e\u3001\u63d2\u5165\u548c\u5220\u9664\u64cd\u4f5c\u3002<\/p>\n<\/p>\n

\u4e00\u3001\u521b\u5efa\u8282\u70b9\u7ed3\u6784<\/h3>\n<\/p>\n

\u8df3\u8868\u7684\u6bcf\u4e2a\u8282\u70b9\u5305\u62ec\u591a\u4e2a\u6307\u5411\u4e0d\u540c\u5c42\u7ea7\u7684\u6307\u9488\uff0c\u5b83\u4eec\u6784\u6210\u4e86\u8df3\u8868\u7684"\u8df3\u8dc3"\u7ed3\u6784\u3002\u5728C\u8bed\u8a00\u4e2d\uff0c\u8282\u70b9\u53ef\u4ee5\u7528\u7ed3\u6784\u4f53\u8868\u793a\uff1a<\/p>\n<\/p>\n

typedef struct SkipListNode {<\/p>\n
    int key;<\/p>\n
    int value;<\/p>\n
    struct SkipListNode forward;<\/p>\n
} SkipListNode;<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8282\u70b9\u4e2d\u7684forward<\/code>\u662f\u4e00\u4e2a\u6307\u9488\u6570\u7ec4\uff0c\u5b58\u50a8\u7740\u6307\u5411\u540c\u4e00\u5c42\u7684\u4e0b\u4e00\u4e2a\u8282\u70b9\u7684\u6307\u9488\uff0c\u5728\u4e0d\u540c\u5c42\u7ea7\u4e2d\uff0c\u8282\u70b9\u53ef\u4ee5\u8df3\u8fc7\u4e00\u5b9a\u6570\u91cf\u7684\u4e2d\u95f4\u8282\u70b9\u63d0\u9ad8\u641c\u7d22\u6548\u7387\u3002<\/p>\n<\/p>\n
\u4e8c\u3001\u521d\u59cb\u5316\u8df3\u8868<\/h3>\n<\/p>\n
\u8df3\u8868\u7684\u521d\u59cb\u5316\u5305\u62ec\u8bbe\u5b9a\u8df3\u8868\u7684\u6700\u5927\u5c42\u6570\u548c\u5f53\u524d\u5c42\u6570\uff0c\u521b\u5efa\u4e00\u4e2a\u5934\u8282\u70b9\uff1a<\/p>\n<\/p>\n
typedef struct SkipList {<\/p>\n
    int level;<\/p>\n
    int maxLevel;<\/p>\n
    SkipListNode *header;<\/p>\n
} SkipList;<\/p>\n
SkipList* createSkipList(int maxLevel) {<\/p>\n
    SkipList *sl = (SkipList *)malloc(sizeof(SkipList));<\/p>\n
    sl->level = 0;<\/p>\n
    sl->maxLevel = maxLevel;<\/p>\n
    sl->header = (SkipListNode *)malloc(sizeof(SkipListNode));<\/p>\n
    sl->header->forward = (SkipListNode )malloc(sizeof(SkipListNode*) * (maxLevel + 1));<\/p>\n
    for (int i = 0; i <= maxLevel; i++) {<\/p>\n
        sl->header->forward[i] = NULL;<\/p>\n
    }<\/p>\n
    return sl;<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u63d2\u5165\u8282\u70b9<\/h3>\n<\/p>\n
\u8df3\u8868\u7684\u63d2\u5165\u64cd\u4f5c\u9996\u5148\u9700\u8981\u51b3\u5b9a\u65b0\u8282\u70b9\u7684\u5c42\u6570\uff0c\u901a\u5e38\u901a\u8fc7\u4e00\u4e2a\u968f\u673a\u8fc7\u7a0b\u5b8c\u6210\u3002\u7136\u540e\u5728\u8df3\u8868\u7684\u4e0d\u540c\u5c42\u7ea7\u4e2d\uff0c\u627e\u5230\u5408\u9002\u7684\u63d2\u5165\u4f4d\u7f6e\uff0c\u63d2\u5165\u65b0\u8282\u70b9\uff1a<\/p>\n<\/p>\n
void insert(SkipList *sl, int key, int value) {<\/p>\n
    SkipListNode *update[sl->maxLevel + 1];<\/p>\n
    SkipListNode *x = sl->header;<\/p>\n
    for (int i = sl->level; i >= 0; i--) {<\/p>\n
        while (x->forward[i] != NULL && x->forward[i]->key < key) {<\/p>\n
            x = x->forward[i];<\/p>\n
        }<\/p>\n
        update[i] = x;<\/p>\n
    }<\/p>\n
    x = x->forward[0];<\/p>\n
    if (x == NULL || x->key != key) {<\/p>\n
        int lvl = randomLevel(sl);<\/p>\n
        if (lvl > sl->level) {<\/p>\n
            for (int i = sl->level + 1; i <= lvl; i++) {<\/p>\n
                update[i] = sl->header;<\/p>\n
            }<\/p>\n
            sl->level = lvl;<\/p>\n
        }<\/p>\n
        x = createNode(lvl, key, value);<\/p>\n
        for (int i = 0; i <= lvl; i++) {<\/p>\n
            x->forward[i] = update[i]->forward[i];<\/p>\n
            update[i]->forward[i] = x;<\/p>\n
        }<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001\u67e5\u627e\u8282\u70b9<\/h3>\n<\/p>\n
\u67e5\u627e\u64cd\u4f5c\u904d\u5386\u8df3\u8868\u5404\u5c42\u7684\u7d22\u5f15\u6765\u5feb\u901f\u5b9a\u4f4d\u8282\u70b9\uff1a<\/p>\n<\/p>\n
SkipListNode* search(SkipList *sl, int key) {<\/p>\n
    SkipListNode *x = sl->header;<\/p>\n
    for (int i = sl->level; i >= 0; i--) {<\/p>\n
        while (x->forward[i] && x->forward[i]->key < key) {<\/p>\n
            x = x->forward[i];<\/p>\n
        }<\/p>\n
    }<\/p>\n
    x = x->forward[0];<\/p>\n
    if (x && x->key == key) {<\/p>\n
        return x;<\/p>\n
    } else {<\/p>\n
        return NULL;<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u5220\u9664\u8282\u70b9<\/h3>\n<\/p>\n
\u5220\u9664\u64cd\u4f5c\u9700\u8981\u5728\u5404\u4e2a\u5c42\u4e2d\u627e\u5230\u76ee\u6807\u8282\u70b9\uff0c\u5e76\u4ece\u5176\u524d\u9a71\u8282\u70b9\u4e2d\u5220\u9664\u76f8\u5e94\u7684\u6307\u9488\uff1a<\/p>\n<\/p>\n
void deleteNode(SkipList *sl, int key) {<\/p>\n
    SkipListNode *update[sl->maxLevel + 1];<\/p>\n
    SkipListNode *x = sl->header;<\/p>\n
    for (int i = sl->level; i >= 0; i--) {<\/p>\n
        while (x->forward[i] != NULL && x->forward[i]->key < key) {<\/p>\n
            x = x->forward[i];<\/p>\n
        }<\/p>\n
        update[i] = x;<\/p>\n
    }<\/p>\n
    x = x->forward[0];<\/p>\n
    if (x && x->key == key) {<\/p>\n
        for (int i = 0; i <= sl->level; i++) {<\/p>\n
            if (update[i]->forward[i] != x) break;<\/p>\n
            update[i]->forward[i] = x->forward[i];<\/p>\n
        }<\/p>\n
        free(x);<\/p>\n
        while (sl->level > 0 && sl->header->forward[sl->level] == NULL) {<\/p>\n
            sl->level--;<\/p>\n
        }<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001\u91ca\u653e\u8df3\u8868<\/h3>\n<\/p>\n
\u6700\u540e\uff0c\u8df3\u8868\u7684\u91ca\u653e\u64cd\u4f5c\u9700\u8981\u91ca\u653e\u6240\u6709\u8282\u70b9\u548c\u8df3\u8868\u7ed3\u6784\u672c\u8eab\uff1a<\/p>\n<\/p>\n
void freeSkipList(SkipList *sl) {<\/p>\n
    SkipListNode *current = sl->header->forward[0];<\/p>\n
    while(current) {<\/p>\n
        SkipListNode *next = current->forward[0];<\/p>\n
        free(current);<\/p>\n
        current = next;<\/p>\n
    }<\/p>\n
    free(sl->header->forward);<\/p>\n
    free(sl->header);<\/p>\n
    free(sl);<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5728\u8df3\u8868\u7684\u5b9e\u9645\u5b9e\u73b0\u4e2d\uff0c\u968f\u673a\u5c42\u51fd\u6570\uff08randomLevel\uff09\u662f\u5173\u952e\uff0c\u5b83\u51b3\u5b9a\u4e86\u65b0\u63d2\u5165\u8282\u70b9\u7684\u5c42\u6570\uff0c\u901a\u5e38\u6839\u636e\u6982\u7387\u6765\u8ba1\u7b97\u3002\u63d2\u5165\u3001\u67e5\u627e\u548c\u5220\u9664\u64cd\u4f5c\u4e2d\uff0c\u8282\u70b9\u7684\u904d\u5386\u90fd\u9700\u8981\u4ece\u6700\u9ad8\u5c42\u9010\u6e10\u5411\u4e0b\uff0c\u76f4\u5230\u627e\u5230\u76ee\u6807\u4f4d\u7f6e\u6216\u8282\u70b9\u3002\u8df3\u8868\u7684\u6027\u80fd\u5728\u5f88\u5927\u7a0b\u5ea6\u4e0a\u53d6\u51b3\u4e8e\u5c42\u6570\u7684\u8bbe\u5b9a\uff0c\u4ee5\u53ca\u8282\u70b9\u5c42\u6570\u7684\u968f\u673a\u5206\u914d\u7b97\u6cd5<\/strong>\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
1. \u8df3\u8868 SkipList \u662f\u4ec0\u4e48\uff1f\u5b83\u6709\u54ea\u4e9b\u5e94\u7528\u573a\u666f\uff1f<\/strong><\/p>\n
\u8df3\u8868 SkipList \u662f\u4e00\u79cd\u968f\u673a\u5316\u7684\u6570\u636e\u7ed3\u6784\uff0c\u7528\u4e8e\u5b9e\u73b0\u6709\u5e8f\u94fe\u8868\u3002\u8df3\u8868\u4e2d\u7684\u8282\u70b9\u5305\u542b\u4e00\u4e2a\u952e\u548c\u4e00\u4e2a\u6307\u5411\u4e0b\u4e00\u4e2a\u8282\u70b9\u7684\u6307\u9488\u6570\u7ec4\u3002\u6bcf\u4e2a\u6307\u9488\u6570\u7ec4\u6709\u591a\u4e2a\u5c42\u7ea7\uff0c\u6bcf\u4e2a\u5c42\u7ea7\u7684\u6307\u9488\u6307\u5411\u4e0b\u4e00\u5c42\u7ea7\u7684\u8282\u70b9\u3002\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\uff0c\u8df3\u8868\u53ef\u4ee5\u5728\u67e5\u627e\u3001\u63d2\u5165\u548c\u5220\u9664\u5143\u7d20\u7684\u64cd\u4f5c\u4e2d\u8fbe\u5230\u5e73\u5747\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O(log n) \u7684\u6548\u679c\u3002<\/p>\n
\u8df3\u8868 SkipList \u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u6709\u591a\u79cd\u4f7f\u7528\u573a\u666f\u3002\u5176\u4e2d\u4e00\u4e9b\u5e94\u7528\u5305\u62ec\u9ad8\u6027\u80fd\u7684\u7d22\u5f15\u6570\u636e\u7ed3\u6784\u3001\u6709\u5e8f\u96c6\u5408\u7684\u5b9e\u73b0\u4ee5\u53ca\u6709\u5e8f\u8303\u56f4\u67e5\u8be2\u7b49\u3002\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u8df3\u8868 SkipList \u53ef\u4ee5\u66ff\u4ee3\u5e73\u8861\u4e8c\u53c9\u6811\uff0c\u4ee5\u63d0\u4f9b\u66f4\u5feb\u7684\u67e5\u8be2\u901f\u5ea6\u3002<\/p>\n
2. \u5982\u4f55\u5b9e\u73b0\u8df3\u8868 SkipList \u7684\u63d2\u5165\u64cd\u4f5c\uff1f<\/strong><\/p>\n
\u8df3\u8868 SkipList \u7684\u63d2\u5165\u64cd\u4f5c\u76f8\u5bf9\u7b80\u5355\u3002\u9996\u5148\uff0c\u9700\u8981\u6839\u636e\u8981\u63d2\u5165\u7684\u5143\u7d20\u786e\u5b9a\u5176\u5e94\u8be5\u5c5e\u4e8e\u7684\u5c42\u7ea7\u3002\u8fd9\u53ef\u4ee5\u901a\u8fc7\u968f\u673a\u6570\u751f\u6210\u5668\u6765\u51b3\u5b9a\u3002\u7136\u540e\uff0c\u4ece\u6700\u9ad8\u5c42\u7ea7\u5f00\u59cb\uff0c\u9010\u5c42\u5411\u4e0b\u641c\u7d22\uff0c\u76f4\u5230\u627e\u5230\u5408\u9002\u7684\u4f4d\u7f6e\u63d2\u5165\u65b0\u5143\u7d20\u3002<\/p>\n
\u5728\u627e\u5230\u5e94\u8be5\u63d2\u5165\u7684\u4f4d\u7f6e\u540e\uff0c\u9700\u8981\u521b\u5efa\u65b0\u8282\u70b9\uff0c\u5e76\u8c03\u6574\u8282\u70b9\u4e4b\u95f4\u7684\u5173\u7cfb\u3002\u65b0\u8282\u70b9\u7684\u6307\u9488\u6570\u7ec4\u5c06\u4f1a\u6307\u5411\u4e0b\u4e00\u5c42\u7ea7\u7684\u8282\u70b9\uff0c\u4ee5\u5e2e\u52a9\u5feb\u901f\u67e5\u627e\u3002\u540c\u65f6\uff0c\u9700\u8981\u66f4\u65b0\u5176\u4ed6\u8282\u70b9\u7684\u6307\u9488\uff0c\u4f7f\u5176\u6307\u5411\u65b0\u63d2\u5165\u7684\u8282\u70b9\u3002<\/p>\n
3. \u5982\u4f55\u5b9e\u73b0\u8df3\u8868 SkipList \u7684\u5220\u9664\u64cd\u4f5c\uff1f<\/strong><\/p>\n
\u8df3\u8868 SkipList \u7684\u5220\u9664\u64cd\u4f5c\u76f8\u5bf9\u590d\u6742\u4e00\u4e9b\u3002\u9996\u5148\uff0c\u9700\u8981\u6839\u636e\u8981\u5220\u9664\u7684\u5143\u7d20\u8fdb\u884c\u641c\u7d22\uff0c\u627e\u5230\u8be5\u5143\u7d20\u5728\u6bcf\u4e00\u5c42\u7ea7\u7684\u524d\u4e00\u4e2a\u8282\u70b9\u3002\u901a\u8fc7\u8fd9\u4e9b\u524d\u4e00\u4e2a\u8282\u70b9\uff0c\u6211\u4eec\u53ef\u4ee5\u51c6\u786e\u5730\u627e\u5230\u8981\u5220\u9664\u7684\u8282\u70b9\u3002<\/p>\n
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