{"id":298,"date":"2025-08-28T10:38:03","date_gmt":"2025-08-28T02:38:03","guid":{"rendered":"https:\/\/heyingnian.com\/?p=298"},"modified":"2025-08-28T10:38:33","modified_gmt":"2025-08-28T02:38:33","slug":"leetcode-238","status":"publish","type":"post","link":"https:\/\/heyingnian.com\/index.php\/2025\/08\/28\/leetcode-238\/","title":{"rendered":"\u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\"><br>\ud83d\udd17 \u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef<\/h1>\n\n\n\n<p>\u9898\u76ee\u6765\u6e90\uff1a<a target=\"_blank\" rel=\"noreferrer noopener\"><a href=\"https:\/\/leetcode.cn\/problems\/product-of-array-except-self\/?envType=study-plan-v2&amp;envId=top-100-liked\" target=\"_blank\" rel=\"noopener\">238. \u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef &#8211; \u529b\u6263\uff08LeetCode\uff09<\/a><\/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\u8fd4\u56de\u6570\u7ec4 <code>answer<\/code>\uff0c\u5176\u4e2d <code>answer[i]<\/code> \u7b49\u4e8e <code>nums<\/code> \u4e2d<strong>\u9664 <code>nums[i]<\/code> \u4e4b\u5916\u5176\u4f59\u5404\u5143\u7d20\u7684\u4e58\u79ef<\/strong>\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8981\u6c42<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u4e0d\u80fd\u4f7f\u7528\u9664\u6cd5\u3002<\/li>\n\n\n\n<li>\u5728\u00a0<code>O(n)<\/code>\u00a0\u65f6\u95f4\u590d\u6742\u5ea6\u5185\u5b8c\u6210\u3002<\/li>\n\n\n\n<li>\u9898\u76ee\u4fdd\u8bc1\u7ed3\u679c\u5728 32 \u4f4d\u6574\u6570\u8303\u56f4\u5185\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>\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 = [1,2,3,4]<\/code><\/li>\n\n\n\n<li>\u8f93\u51fa\uff1a<code>[24,12,8,6]<\/code><\/li>\n\n\n\n<li>\u89e3\u91ca\uff1a\n<ul class=\"wp-block-list\">\n<li><code>answer[0] = 2*3*4 = 24<\/code><\/li>\n\n\n\n<li><code>answer[1] = 1*3*4 = 12<\/code><\/li>\n\n\n\n<li><code>answer[2] = 1*2*4 = 8<\/code><\/li>\n\n\n\n<li><code>answer[3] = 1*2*3 = 6<\/code><\/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 = [-1,1,0,-3,3]<\/code><\/li>\n\n\n\n<li>\u8f93\u51fa\uff1a<code>[0,0,9,0,0]<\/code><\/li>\n\n\n\n<li>\u89e3\u91ca\uff1a\n<ul class=\"wp-block-list\">\n<li>\u7531\u4e8e\u6570\u7ec4\u4e2d\u5b58\u5728\u00a0<code>0<\/code>\uff0c\u9664\u00a0<code>nums[2]<\/code>\u00a0\u5916\u7684\u6240\u6709\u00a0<code>answer[i]<\/code>\u00a0\u90fd\u5305\u542b\u00a0<code>0<\/code>\uff0c\u6545\u4e3a\u00a0<code>0<\/code>\u3002<\/li>\n\n\n\n<li><code>answer[2] = (-1)*1*(-3)*3 = 9<\/code><\/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>\u26a0\ufe0f \u63d0\u793a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>2 &lt;= nums.length &lt;= 10\u2075<\/code><\/li>\n\n\n\n<li><code>-30 &lt;= nums[i] &lt;= 30<\/code><\/li>\n\n\n\n<li>\u7ed3\u679c\u4fdd\u8bc1\u5728 32 \u4f4d\u6574\u6570\u8303\u56f4\u5185<\/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\u524d\u7f00\u4e58\u79ef + \u540e\u7f00\u4e58\u79ef\uff08\u4e24\u6b21\u904d\u5386\uff09\u2014\u2014 O(n) \u65f6\u95f4\uff0cO(1) \u989d\u5916\u7a7a\u95f4<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class Solution {\n    public int&#91;] productExceptSelf(int&#91;] nums) {\n        int n = nums.length;\n        int&#91;] result = new int&#91;n];\n      \n        result&#91;0] = 1;\n        for (int i = 1; i &lt; n; i++) {\n            result&#91;i] = result&#91;i - 1] * nums&#91;i - 1];\n        }\n     \n        int right = 1; \n        for (int i = n - 1; i >= 0; i--) {\n            result&#91;i] = result&#91;i] * right; \n            right = right * nums&#91;i]; \n        }\n        \n        return 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)<\/strong>\n<ul class=\"wp-block-list\">\n<li>\u7b2c\u4e00\u6b21\u904d\u5386\u8ba1\u7b97\u524d\u7f00\u4e58\u79ef\uff1aO(n)<\/li>\n\n\n\n<li>\u7b2c\u4e8c\u6b21\u904d\u5386\u8ba1\u7b97\u540e\u7f00\u4e58\u79ef\u5e76\u66f4\u65b0\u7ed3\u679c\uff1aO(n)<\/li>\n\n\n\n<li>\u603b\u4f53\u4e3a\u7ebf\u6027\u65f6\u95f4\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(1)<\/strong>\uff08\u4e0d\u8ba1\u8fd4\u56de\u6570\u7ec4\uff09\n<ul class=\"wp-block-list\">\n<li><code>result<\/code>\u00a0\u6570\u7ec4\u4e3a\u8fd4\u56de\u503c\uff0c\u4e0d\u8ba1\u5165\u989d\u5916\u7a7a\u95f4\u3002<\/li>\n\n\n\n<li>\u4ec5\u4f7f\u7528\u5e38\u6570\u53d8\u91cf\u00a0<code>right<\/code>\uff0c\u6ee1\u8db3\u9898\u76ee\u5bf9\u7a7a\u95f4\u7684\u8981\u6c42\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>\u6838\u5fc3\u601d\u60f3\uff1a\u5206\u89e3\u4e3a\u524d\u7f00\u4e0e\u540e\u7f00\u4e58\u79ef<\/strong><br>\u5bf9\u4e8e\u4efb\u610f\u4f4d\u7f6e <code>i<\/code>\uff0c<code>answer[i] = (nums[0] * ... * nums[i-1]) * (nums[i+1] * ... * nums[n-1])<\/code><br>\u5373\uff1a<strong>\u5de6\u8fb9\u6240\u6709\u5143\u7d20\u7684\u4e58\u79ef \u00d7 \u53f3\u8fb9\u6240\u6709\u5143\u7d20\u7684\u4e58\u79ef<\/strong><\/li>\n\n\n\n<li><strong>\u4e24\u6b65\u8d70\u7b56\u7565<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li><strong>\u6b65\u9aa4 1\uff1a\u8ba1\u7b97\u524d\u7f00\u4e58\u79ef<\/strong><br>\u4f7f\u7528 <code>result<\/code> \u6570\u7ec4\u5148\u5b58\u50a8\u6bcf\u4e2a\u4f4d\u7f6e <code>i<\/code> \u7684<strong>\u5de6\u4fa7\u5143\u7d20\u4e58\u79ef<\/strong>\u3002\n<ul class=\"wp-block-list\">\n<li><code>result[0] = 1<\/code>\uff08\u5de6\u8fb9\u65e0\u5143\u7d20\uff09<\/li>\n\n\n\n<li><code>result[i] = result[i-1] * nums[i-1]<\/code>\uff08\u9012\u63a8\uff09<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u6b65\u9aa4 2\uff1a\u8ba1\u7b97\u540e\u7f00\u4e58\u79ef\u5e76\u5408\u5e76<\/strong><br>\u4ece\u53f3\u5411\u5de6\u904d\u5386\uff0c\u7528\u53d8\u91cf <code>right<\/code> \u52a8\u6001\u7ef4\u62a4\u5f53\u524d\u4f4d\u7f6e <code>i<\/code> \u7684<strong>\u53f3\u4fa7\u5143\u7d20\u4e58\u79ef<\/strong>\u3002\n<ul class=\"wp-block-list\">\n<li>\u521d\u59cb\u00a0<code>right = 1<\/code>\uff08\u6700\u53f3\u5143\u7d20\u53f3\u8fb9\u65e0\u5143\u7d20\uff09<\/li>\n\n\n\n<li><code>result[i] *= right<\/code>\uff1a\u5c06\u53f3\u4fa7\u4e58\u79ef\u4e58\u5230\u7ed3\u679c\u4e2d<\/li>\n\n\n\n<li><code>right *= nums[i]<\/code>\uff1a\u66f4\u65b0\u00a0<code>right<\/code>\uff0c\u4e3a\u4e0b\u4e00\u8f6e\uff08i-1\uff09\u51c6\u5907<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u4e3e\u4f8b\u8bf4\u660e<\/strong>\uff1a<br>\u5bf9 <code>nums = [1,2,3,4]<\/code>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u6b65\u9aa4 1 \u540e\uff1a<code>result = [1, 1, 2, 6]<\/code>\n<ul class=\"wp-block-list\">\n<li><code>result[1] = 1 * nums[0] = 1<\/code><\/li>\n\n\n\n<li><code>result[2] = 1 * nums[1] = 2<\/code><\/li>\n\n\n\n<li><code>result[3] = 2 * nums[2] = 6<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u6b65\u9aa4 2 \u8fc7\u7a0b\uff1a\n<ul class=\"wp-block-list\">\n<li>i=3:\u00a0<code>result[3] = 6 * 1 = 6<\/code>,\u00a0<code>right = 1 * 4 = 4<\/code><\/li>\n\n\n\n<li>i=2:\u00a0<code>result[2] = 2 * 4 = 8<\/code>,\u00a0<code>right = 4 * 3 = 12<\/code><\/li>\n\n\n\n<li>i=1:\u00a0<code>result[1] = 1 * 12 = 12<\/code>,\u00a0<code>right = 12 * 2 = 24<\/code><\/li>\n\n\n\n<li>i=0:\u00a0<code>result[0] = 1 * 24 = 24<\/code>,\u00a0<code>right = 24 * 1 = 24<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u6700\u7ec8\u00a0<code>result = [24,12,8,6]<\/code>\u00a0\u2705<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u5904\u7406\u7279\u6b8a\u60c5\u51b5\uff08\u542b 0\uff09<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u8be5\u65b9\u6cd5\u5929\u7136\u652f\u6301\u00a0<code>0<\/code>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u82e5\u00a0<code>nums[i] = 0<\/code>\uff0c\u5219\u00a0<code>result[i]<\/code>\u00a0\u53ea\u5305\u542b\u5de6\u4fa7\u4e58\u79ef\uff0c\u53f3\u4fa7\u4e58\u79ef\u7531\u00a0<code>right<\/code>\u00a0\u4f20\u9012<\/li>\n\n\n\n<li>\u5982\u793a\u4f8b 2\uff0c<code>right<\/code>\u00a0\u5728\u9047\u5230\u00a0<code>0<\/code>\u00a0\u524d\u4e3a\u00a0<code>3<\/code>\uff0c\u5728\u00a0<code>i=2<\/code>\u00a0\u65f6\u00a0<code>result[2] = 2 * 3 = 6<\/code>\uff1f<\/li>\n\n\n\n<li>\u5b9e\u9645\u8fc7\u7a0b\u4f1a\u6b63\u786e\u8ba1\u7b97\uff1a<code>right<\/code>\u00a0\u4f1a\u56e0\u00a0<code>0<\/code>\u00a0\u800c\u53d8\u4e3a\u00a0<code>0<\/code>\uff0c\u540e\u7eed\u00a0<code>result[i]<\/code>\u00a0\u4e5f\u53d8\u4e3a\u00a0<code>0<\/code>\uff0c\u4f46\u00a0<code>i=2<\/code>\u00a0\u65f6\u00a0<code>right<\/code>\u00a0\u8fd8\u672a\u4e58\u00a0<code>0<\/code>\uff0c\u56e0\u6b64\u80fd\u6b63\u786e\u5f97\u5230\u00a0<code>9<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\ud83d\udd17 \u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef \u9898\u76ee\u6765\u6e90\uff1a238. \u9664\u81ea\u8eab\u4ee5\u5916\u6570\u7ec4\u7684\u4e58\u79ef &#8211; \u529b\u6263\uff08LeetCode\uff09  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30,12],"tags":[26,31,14],"class_list":["post-298","post","type-post","status-publish","format-standard","hentry","category-ordinary_arrays","category-algorithm","tag-prefix_sum","tag-array","tag-algorithm"],"_links":{"self":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/298","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=298"}],"version-history":[{"count":1,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/298\/revisions"}],"predecessor-version":[{"id":299,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/298\/revisions\/299"}],"wp:attachment":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/media?parent=298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/categories?post=298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/tags?post=298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}