{"id":900,"date":"2025-10-24T22:43:17","date_gmt":"2025-10-24T14:43:17","guid":{"rendered":"https:\/\/www.guanhaobo.cn\/?p=900"},"modified":"2025-10-24T22:43:17","modified_gmt":"2025-10-24T14:43:17","slug":"leetcode-41-%e7%bc%ba%e5%a4%b1%e7%9a%84%e7%ac%ac%e4%b8%80%e4%b8%aa%e6%ad%a3%e6%95%b0","status":"publish","type":"post","link":"https:\/\/www.guanhaobo.cn\/?p=900","title":{"rendered":"LeetCode 41 \u2013 \u7f3a\u5931\u7684\u7b2c\u4e00\u4e2a\u6b63\u6570"},"content":{"rendered":"

\u9898\u76ee\u63cf\u8ff0<\/h1>\n

\u7ed9\u4f60\u4e00\u4e2a\u672a\u6392\u5e8f\u7684\u6574\u6570\u6570\u7ec4 nums \uff0c\u8bf7\u4f60\u627e\u51fa\u5176\u4e2d\u6ca1\u6709\u51fa\u73b0\u7684\u6700\u5c0f\u7684\u6b63\u6574\u6570\u3002<\/p>\n

\u8bf7\u4f60\u5b9e\u73b0\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O(n) \u5e76\u4e14\u53ea\u4f7f\u7528\u5e38\u6570\u7ea7\u522b\u989d\u5916\u7a7a\u95f4\u7684\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n

\u793a\u4f8b 1\uff1a<\/p>\n

\u8f93\u5165\uff1anums = [1,2,0]
\n\u8f93\u51fa\uff1a3
\n\u89e3\u91ca\uff1a\u8303\u56f4 [1,2] \u4e2d\u7684\u6570\u5b57\u90fd\u5728\u6570\u7ec4\u4e2d\u3002<\/p>\n

\u9898\u76ee\u5206\u6790<\/h1>\n

\u4f4d\u7f6e\u7f6e\u6362\uff0c\u54c8\u5e0c\u8868\u7684\u601d\u60f3.
\n\u6570\u7ec4\u5927\u5c0f\u4e3a n\uff0c\u5219\u7f3a\u5931\u7684\u7b2c\u4e00\u4e2a\u6b63\u6570\u5728 [1, n + 1] \u5185
\n\u5728\u6570\u7ec4\u5185\u8fdb\u884c\u4f4d\u7f6e\u7f6e\u6362\uff0c\u4fdd\u8bc1\u6570\u5b57 x \u653e\u5728 x – 1 \u7684\u4f4d\u7f6e\u4e0a\uff08\u8d85\u51fa\u8303\u56f4\u5219\u4e0d\u505a\u5904\u7406\uff09\u3002
\n\u6700\u540e\u4ece\u5934\u904d\u5386\u4e00\u6b21\uff0c\u7b2c\u4e00\u4e2a\u4e0d\u7b26\u5408\u89c4\u5219\u7684\u4f4d\u7f6e\uff0c\u5373\u662f\u7f3a\u5c11\u7684\u6b63\u6570\u3002
\n\u5982\u679c n \u4e2a\u6570\u5b57\u5168\u90fd\u7b26\u5408\u89c4\u5219\uff0c\u5219\u7b54\u6848\u662f n + 1
\n\u65f6\u95f4\u590d\u6742\u5ea6 O(n), \u7a7a\u95f4\u590d\u6742\u5ea6 O(1)<\/p>\n

Java<\/h1>\n
public int firstMissingPositive(int[] nums) {\n    int n = nums.length;\n    for (int i = 0; i < n; i++) {\n        int x = nums[i];\n        while (x <= n && x > 0 && nums[x - 1] != x) {\n            int temp = nums[x - 1];\n            nums[x - 1] = x;\n            nums[i] = temp;\n            x = nums[i];\n        }\n    }\n    for (int i = 0; i < n; i++) {\n        if (nums[i] != i + 1) {\n            return i + 1;\n        }\n    }\n    return n + 1;\n}\n<\/code><\/pre>\n
Kotlin<\/h1>\n
fun firstMissingPositive(nums: IntArray): Int {\n    val n = nums.size\n    for (i in nums.indices) {\n        var x = nums[i]\n        while (x in 1..n && nums[x - 1] != x) {\n            val temp = nums[x - 1]\n            nums[x - 1] = x\n            nums[i] = temp\n            x = nums[i]\n        }\n    }\n    for (i in nums.indices) {\n        if (nums[i] != i + 1) {\n            return i + 1\n        }\n    }\n    return n + 1\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u9898\u76ee\u63cf\u8ff0 \u7ed9\u4f60\u4e00\u4e2a\u672a\u6392\u5e8f\u7684\u6574\u6570\u6570\u7ec4 nums \uff0c\u8bf7\u4f60\u627e\u51fa\u5176\u4e2d\u6ca1\u6709\u51fa\u73b0\u7684\u6700\u5c0f\u7684\u6b63\u6574\u6570\u3002 \u8bf7\u4f60\u5b9e\u73b0\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[20,74,73],"class_list":["post-900","post","type-post","status-publish","format-standard","hentry","category-algo","tag-leetcode","tag-74","tag-73"],"_links":{"self":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/900","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=900"}],"version-history":[{"count":1,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/900\/revisions"}],"predecessor-version":[{"id":901,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/900\/revisions\/901"}],"wp:attachment":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=900"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=900"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}