{"id":132,"date":"2025-08-22T15:47:48","date_gmt":"2025-08-22T07:47:48","guid":{"rendered":"https:\/\/heyingnian.com\/?p=132"},"modified":"2025-08-22T16:45:52","modified_gmt":"2025-08-22T08:45:52","slug":"leetcode-15","status":"publish","type":"post","link":"https:\/\/heyingnian.com\/index.php\/2025\/08\/22\/leetcode-15\/","title":{"rendered":"\u4e09\u6570\u4e4b\u548c"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\">\ud83d\udd17 \u4e09\u6570\u4e4b\u548c<\/h1>\n\n\n\n<p>\u9898\u76ee\u6765\u6e90\uff1a<a target=\"_blank\" rel=\"noreferrer noopener\">15. \u4e09\u6570\u4e4b\u548c &#8211; \u529b\u6263\uff08LeetCode\uff09<\/a><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\ud83d\udccc \u9898\u76ee\u63cf\u8ff0<\/p>\n\n\n\n<p>\u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 <code>nums<\/code>\uff0c\u5224\u65ad\u662f\u5426\u5b58\u5728\u4e09\u5143\u7ec4 <code>[nums[i], nums[j], nums[k]]<\/code> \u6ee1\u8db3\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>i != j<\/code>\u3001<code>i != k<\/code>\u00a0\u4e14\u00a0<code>j != k<\/code><\/li>\n\n\n\n<li>\u540c\u65f6\u6ee1\u8db3\u00a0<code>nums[i] + nums[j] + nums[k] == 0<\/code><\/li>\n<\/ul>\n\n\n\n<p>\u8bf7\u4f60\u8fd4\u56de\u6240\u6709\u548c\u4e3a <code>0<\/code> \u4e14<strong>\u4e0d\u91cd\u590d<\/strong>\u7684\u4e09\u5143\u7ec4\u3002<\/p>\n\n\n\n<p><strong>\u6ce8\u610f<\/strong>\uff1a\u7b54\u6848\u4e2d\u4e0d\u53ef\u4ee5\u5305\u542b\u91cd\u590d\u7684\u4e09\u5143\u7ec4\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u2705 \u793a\u4f8b\u89e3\u6790<\/p>\n\n\n\n<p>\u793a\u4f8b 1\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8f93\u5165\uff1a<code>nums = [-1, 0, 1, 2, -1, -4]<\/code><\/li>\n\n\n\n<li>\u8f93\u51fa\uff1a<code>[[-1, -1, 2], [-1, 0, 1]]<\/code><\/li>\n\n\n\n<li>\u89e3\u91ca\uff1a\n<ul class=\"wp-block-list\">\n<li><code>(-1) + 0 + 1 = 0<\/code>\u00a0\u2192\u00a0<code>[-1, 0, 1]<\/code><\/li>\n\n\n\n<li><code>(-1) + (-1) + 2 = 0<\/code>\u00a0\u2192\u00a0<code>[-1, -1, 2]<\/code><br>\u4e0d\u540c\u7684\u4e09\u5143\u7ec4\u662f\u00a0<code>[-1,0,1]<\/code>\u00a0\u548c\u00a0<code>[-1,-1,2]<\/code>\u3002\u8f93\u51fa\u987a\u5e8f\u4e0d\u9650\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>\u793a\u4f8b 2\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8f93\u5165\uff1a<code>nums = [0, 1, 1]<\/code><\/li>\n\n\n\n<li>\u8f93\u51fa\uff1a<code>[]<\/code><\/li>\n\n\n\n<li>\u89e3\u91ca\uff1a\u65e0\u6cd5\u627e\u5230\u4e09\u4e2a\u6570\u4f7f\u5176\u548c\u4e3a\u00a0<code>0<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u793a\u4f8b 3\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8f93\u5165\uff1a<code>nums = [0, 0, 0]<\/code><\/li>\n\n\n\n<li>\u8f93\u51fa\uff1a<code>[[0, 0, 0]]<\/code><\/li>\n\n\n\n<li>\u89e3\u91ca\uff1a\u552f\u4e00\u6ee1\u8db3\u6761\u4ef6\u7684\u4e09\u5143\u7ec4\u662f\u00a0<code>[0, 0, 0]<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u26a0\ufe0f \u63d0\u793a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>3 &lt;= nums.length &lt;= 3000<\/code><\/li>\n\n\n\n<li><code>-10\u2075 &lt;= nums[i] &lt;= 10\u2075<\/code><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\ud83d\udca1 \u89e3\u6cd5\uff1a\u6392\u5e8f + \u53cc\u6307\u9488\uff08\u53bb\u91cd\u4f18\u5316\uff09\u2014\u2014 O(n\u00b2) \u65f6\u95f4<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\n<strong>class<\/strong> <strong>Solution<\/strong> {\n    <strong>public<\/strong> List&lt;List&lt;Integer>> threeSum(<strong>int<\/strong>&#91;] nums) {\n        List&lt;List&lt;Integer>> result = <strong>new<\/strong> ArrayList&lt;>();\n        Arrays.sort(nums); \/\/ \u6392\u5e8f\u4ee5\u4fbf\u4f7f\u7528\u53cc\u6307\u9488\u548c\u53bb\u91cd\n\n        <strong>for<\/strong> (<strong>int<\/strong> i = 0; i &lt; nums.length - 2; i++) {\n            \/\/ \u8df3\u8fc7\u91cd\u590d\u7684\u57fa\u51c6\u503c\uff08\u53bb\u91cd\u7b2c\u4e00\u4e2a\u6570\uff09\n            <strong>if<\/strong> (i > 0 &amp;&amp; nums&#91;i] == nums&#91;i - 1]) {\n                <strong>continue<\/strong>;\n            }\n\n            \/\/ \u4f18\u53161\uff1a\u6700\u5c0f\u4e09\u6570\u548c > 0\uff0c\u4e0d\u53ef\u80fd\u627e\u5230\u89e3\n            <strong>if<\/strong> (nums&#91;i] + nums&#91;i + 1] + nums&#91;i + 2] > 0) {\n                <strong>break<\/strong>;\n            }\n\n            \/\/ \u4f18\u53162\uff1a\u5f53\u524d\u503c\u4e0e\u6700\u5927\u4e24\u4e2a\u6570\u4e4b\u548c &lt; 0\uff0c\u8bf4\u660e\u592a\u5c0f\u4e86\uff0c\u7ee7\u7eed\u589e\u5927 i\n            <strong>if<\/strong> (nums&#91;i] + nums&#91;nums.length - 1] + nums&#91;nums.length - 2] &lt; 0) {\n                <strong>continue<\/strong>;\n            }\n\n            <strong>int<\/strong> left = i + 1;\n            <strong>int<\/strong> right = nums.length - 1;\n\n            <strong>while<\/strong> (left &lt; right) {\n                <strong>int<\/strong> sum = nums&#91;i] + nums&#91;left] + nums&#91;right];\n\n                <strong>if<\/strong> (sum == 0) {\n                    result.add(Arrays.asList(nums&#91;i], nums&#91;left], nums&#91;right]));\n\n                    \/\/ \u53bb\u91cd\uff1a\u8df3\u8fc7\u76f8\u540c\u7684 left \u548c right \u503c\n                    <strong>while<\/strong> (left &lt; right &amp;&amp; nums&#91;left] == nums&#91;left + 1]) {\n                        left++;\n                    }\n                    <strong>while<\/strong> (left &lt; right &amp;&amp; nums&#91;right] == nums&#91;right - 1]) {\n                        right--;\n                    }\n\n                    \/\/ \u79fb\u52a8\u5230\u4e0b\u4e00\u4e2a\u4e0d\u540c\u503c\u7684\u4f4d\u7f6e\n                    left++;\n                    right--;\n                } <strong>else<\/strong> <strong>if<\/strong> (sum &lt; 0) {\n                    left++; \n                } <strong>else<\/strong> {\n                    right--; \n                }\n            }\n        }\n\n        <strong>return<\/strong> result;\n    }\n}<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\ud83d\udcca \u590d\u6742\u5ea6\u5206\u6790<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u65f6\u95f4\u590d\u6742\u5ea6\uff1aO(n\u00b2)<\/strong>\n<ul class=\"wp-block-list\">\n<li>\u6392\u5e8f\uff1aO(n log n)<\/li>\n\n\n\n<li>\u5916\u5c42\u5faa\u73af\u904d\u5386\u00a0<code>i<\/code>\uff1aO(n)<\/li>\n\n\n\n<li>\u5185\u5c42\u53cc\u6307\u9488\u904d\u5386\uff1aO(n)<\/li>\n\n\n\n<li>\u603b\u4f53\uff1aO(n\u00b2)\uff0c\u4e3b\u5bfc\u9879\u4e3a\u4e24\u5c42\u5d4c\u5957\u5faa\u73af\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(1)<\/strong>\n<ul class=\"wp-block-list\">\n<li>\u4e0d\u8003\u8651\u8fd4\u56de\u7ed3\u679c\u6240\u5360\u7528\u7684\u7a7a\u95f4\uff0c\u4ec5\u4f7f\u7528\u5e38\u6570\u989d\u5916\u7a7a\u95f4\uff08<code>i<\/code>,\u00a0<code>left<\/code>,\u00a0<code>right<\/code>,\u00a0<code>sum<\/code>\u00a0\u7b49\u53d8\u91cf\uff09\u3002<\/li>\n\n\n\n<li>\u82e5\u8ba1\u5165\u7ed3\u679c\u7a7a\u95f4\uff0c\u5219\u4e3a O(k)\uff0c\u5176\u4e2d k \u4e3a\u6ee1\u8db3\u6761\u4ef6\u7684\u4e09\u5143\u7ec4\u6570\u91cf\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\ud83e\udde9 \u89e3\u9898\u601d\u8def<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u6392\u5e8f\u9884\u5904\u7406<\/strong>\uff1a<br>\u5148\u5bf9\u6570\u7ec4\u6392\u5e8f\uff0c\u4fbf\u4e8e\u540e\u7eed\u4f7f\u7528\u53cc\u6307\u9488\uff0c\u5e76\u652f\u6301\u53bb\u91cd\u5224\u65ad\u3002<\/li>\n\n\n\n<li><strong>\u56fa\u5b9a\u4e00\u4e2a\u6570\uff0c\u8f6c\u5316\u4e3a\u4e24\u6570\u4e4b\u548c\u95ee\u9898<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u679a\u4e3e\u7b2c\u4e00\u4e2a\u6570\u00a0<code>nums[i]<\/code>\uff0c\u7136\u540e\u5728\u00a0<code>i+1<\/code>\u00a0\u5230\u00a0<code>n-1<\/code>\u00a0\u8303\u56f4\u5185\u5bfb\u627e\u4e24\u4e2a\u6570\uff0c\u4f7f\u5176\u548c\u4e3a\u00a0<code>-nums[i]<\/code>\u3002<\/li>\n\n\n\n<li>\u8fd9\u5c31\u8f6c\u5316\u4e3a\u7ecf\u5178\u7684\u201c\u4e24\u6570\u4e4b\u548c\u201d\u95ee\u9898\uff0c\u53ef\u7528\u53cc\u6307\u9488\u9ad8\u6548\u89e3\u51b3\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u53cc\u6307\u9488\u6280\u5de7<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li><code>left = i + 1<\/code>\uff0c<code>right = n - 1<\/code><\/li>\n\n\n\n<li>\u82e5\u4e09\u6570\u4e4b\u548c\u00a0<code>== 0<\/code>\uff1a\u8bb0\u5f55\u7ed3\u679c\uff0c\u5e76\u8df3\u8fc7\u91cd\u590d\u503c\uff0c\u53cc\u6307\u9488\u540c\u65f6\u6536\u7f29\u3002<\/li>\n\n\n\n<li>\u82e5\u548c\u00a0<code>&lt; 0<\/code>\uff1a\u8bf4\u660e\u5de6\u8fb9\u592a\u5c0f\uff0c<code>left++<\/code><\/li>\n\n\n\n<li>\u82e5\u548c\u00a0<code>> 0<\/code>\uff1a\u8bf4\u660e\u53f3\u8fb9\u592a\u5927\uff0c<code>right--<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u5173\u952e\u53bb\u91cd\u903b\u8f91<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u5916\u5c42\u00a0<code>i<\/code>\u00a0\u53bb\u91cd\uff1a<code>if (i > 0 &amp;&amp; nums[i] == nums[i-1]) continue;<\/code><\/li>\n\n\n\n<li>\u5185\u5c42\u00a0<code>left<\/code>\u00a0\u548c\u00a0<code>right<\/code>\u00a0\u53bb\u91cd\uff1a\u5728\u627e\u5230\u89e3\u540e\uff0c\u8df3\u8fc7\u76f8\u540c\u503c\uff0c\u907f\u514d\u91cd\u590d\u4e09\u5143\u7ec4\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u526a\u679d\u4f18\u5316<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u82e5\u5f53\u524d\u00a0<code>i<\/code>\u00a0\u5bf9\u5e94\u7684\u6700\u5c0f\u4e09\u6570\u548c > 0\uff0c\u5219\u540e\u7eed\u66f4\u5927\u503c\u4e0d\u53ef\u80fd\u6ee1\u8db3\u6761\u4ef6\uff0c\u76f4\u63a5\u00a0<code>break<\/code>\u3002<\/li>\n\n\n\n<li>\u82e5\u5f53\u524d\u00a0<code>i<\/code>\u00a0\u4e0e\u6700\u5927\u4e24\u6570\u4e4b\u548c &lt; 0\uff0c\u8bf4\u660e\u592a\u5c0f\uff0c<code>continue<\/code>\u00a0\u5c1d\u8bd5\u4e0b\u4e00\u4e2a\u00a0<code>i<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\ud83d\udd17 \u4e09\u6570\u4e4b\u548c \u9898\u76ee\u6765\u6e90\uff1a15. \u4e09\u6570\u4e4b\u548c &#8211; \u529b\u6263\uff08LeetCode\uff09 \ud83d\udccc \u9898\u76ee\u63cf\u8ff0 \u7ed9\u4f60\u4e00\u4e2a\u6574\u6570 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20,12],"tags":[16,14],"class_list":["post-132","post","type-post","status-publish","format-standard","hentry","category-double_pointers","category-algorithm","tag-double_pointers","tag-algorithm"],"_links":{"self":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/132","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/comments?post=132"}],"version-history":[{"count":2,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/132\/revisions"}],"predecessor-version":[{"id":134,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/132\/revisions\/134"}],"wp:attachment":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/media?parent=132"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/categories?post=132"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/tags?post=132"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}