{"id":377,"date":"2025-09-09T18:58:38","date_gmt":"2025-09-09T10:58:38","guid":{"rendered":"https:\/\/heyingnian.com\/?p=377"},"modified":"2025-09-09T19:00:09","modified_gmt":"2025-09-09T11:00:09","slug":"leetcode-2","status":"publish","type":"post","link":"https:\/\/heyingnian.com\/index.php\/2025\/09\/09\/leetcode-2\/","title":{"rendered":"\u4e24\u6570\u76f8\u52a0"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\">\ud83d\udd17 \u4e24\u6570\u76f8\u52a0<\/h1>\n\n\n\n<p>\u9898\u76ee\u6765\u6e90\uff1a<a href=\"https:\/\/leetcode.cn\/problems\/add-two-numbers\/description\/?envType=study-plan-v2&amp;envId=top-100-liked\" target=\"_blank\" rel=\"noopener\">2. \u4e24\u6570\u76f8\u52a0 &#8211; \u529b\u6263\uff08LeetCode\uff09<\/a><\/p>\n\n\n\n<p>\ud83d\udccc \u9898\u76ee\u63cf\u8ff0<\/p>\n\n\n\n<p>\u7ed9\u4f60\u4e24\u4e2a<strong>\u975e\u7a7a<\/strong>\u7684\u94fe\u8868\uff0c\u8868\u793a\u4e24\u4e2a<strong>\u975e\u8d1f\u6574\u6570<\/strong>\u3002\u5b83\u4eec\u6bcf\u4f4d\u6570\u5b57\u90fd\u662f\u6309\u7167<strong>\u9006\u5e8f<\/strong>\u7684\u65b9\u5f0f\u5b58\u50a8\u7684\uff0c\u5e76\u4e14\u6bcf\u4e2a\u8282\u70b9\u53ea\u80fd\u5b58\u50a8<strong>\u4e00\u4f4d\u6570\u5b57<\/strong>\u3002<\/p>\n\n\n\n<p>\u8bf7\u4f60\u5c06\u4e24\u4e2a\u6570\u76f8\u52a0\uff0c\u5e76\u4ee5<strong>\u76f8\u540c\u5f62\u5f0f<\/strong>\u8fd4\u56de\u4e00\u4e2a\u8868\u793a\u548c\u7684\u94fe\u8868\u3002<\/p>\n\n\n\n<p>\u4f60\u53ef\u4ee5\u5047\u8bbe\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9664\u4e86\u6570\u5b57 0 \u4e4b\u5916\uff0c\u8fd9\u4e24\u4e2a\u6570\u90fd\u4e0d\u4f1a\u4ee5 0 \u5f00\u5934\u3002<\/li>\n\n\n\n<li>\u94fe\u8868\u8868\u793a\u7684\u6570\u5b57\u4e0d\u542b\u524d\u5bfc\u96f6\u3002<\/li>\n<\/ul>\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<figure class=\"wp-block-image size-full\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/heyingnian.com\/wp-content\/uploads\/2025\/09\/image-22.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"483\" height=\"342\" data-original=\"https:\/\/heyingnian.com\/wp-content\/uploads\/2025\/09\/image-22.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-378\"  sizes=\"auto, (max-width: 483px) 100vw, 483px\" \/><\/div><\/figure>\n\n\n\n<p>\u8f93\u5165\uff1a<code>l1 = [2,4,3]<\/code>, <code>l2 = [5,6,4]<\/code><br>\u8f93\u51fa\uff1a<code>[7,0,8]<\/code><\/p>\n\n\n\n<p>\u793a\u4f8b 2\uff1a<\/p>\n\n\n\n<p>\u8f93\u5165\uff1a<code>l1 = [0]<\/code>, <code>l2 = [0]<\/code><br>\u8f93\u51fa\uff1a<code>[0]<\/code><\/p>\n\n\n\n<p>\u793a\u4f8b 3\uff1a<\/p>\n\n\n\n<p>\u8f93\u5165\uff1a<code>l1 = [9,9,9,9,9,9,9]<\/code>, <code>l2 = [9,9,9,9]<\/code><br>\u8f93\u51fa\uff1a<code>[8,9,9,9,0,0,0,1]<\/code><\/p>\n\n\n\n<p>\u26a0\ufe0f \u63d0\u793a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6bcf\u4e2a\u94fe\u8868\u4e2d\u7684\u8282\u70b9\u6570\u5728\u8303\u56f4\u00a0<code>[1, 100]<\/code>\u00a0\u5185<\/li>\n\n\n\n<li><code>0 &lt;= Node.val &lt;= 9<\/code><\/li>\n\n\n\n<li>\u9898\u76ee\u6570\u636e\u4fdd\u8bc1\u5217\u8868\u8868\u793a\u7684\u6570\u5b57\u4e0d\u542b\u524d\u5bfc\u96f6<\/li>\n<\/ul>\n\n\n\n<p>\ud83d\udca1 \u89e3\u6cd5\uff1a\u6a21\u62df\u7ad6\u5f0f\u52a0\u6cd5 + \u865a\u62df\u5934\u8282\u70b9 \u2014\u2014 O(max(m,n)) \u65f6\u95f4\uff0cO(1) \u7a7a\u95f4<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class Solution {\n    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {\n        int carry = 0; \n        ListNode dummy = new ListNode(0); \n        ListNode p = dummy;\n\n        while (l1 != null || l2 != null || carry != 0) { \n            int sum = carry;\n            if (l1 != null) {\n                sum += l1.val;\n                l1 = l1.next;\n            }\n            if (l2 != null) {\n                sum += l2.val;\n                l2 = l2.next;\n            }\n            carry = sum \/ 10;\n            p.next = new ListNode(sum % 10);\n            p = p.next;\n        }\n\n        return dummy.next;\n    }\n}<\/code><\/pre>\n\n\n\n<p>\ud83d\udcca \u590d\u6742\u5ea6\u5206\u6790<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u65f6\u95f4\u590d\u6742\u5ea6\uff1aO(max(m, n))\n<ul class=\"wp-block-list\">\n<li>m\u3001n \u5206\u522b\u4e3a\u4e24\u4e2a\u94fe\u8868\u957f\u5ea6\uff0c\u9700\u904d\u5386\u8f83\u957f\u94fe\u8868 + \u53ef\u80fd\u7684\u8fdb\u4f4d\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(1) \u2705\uff08\u4e0d\u8ba1\u7ed3\u679c\u94fe\u8868\u7a7a\u95f4\uff09\n<ul class=\"wp-block-list\">\n<li>\u4ec5\u4f7f\u7528\u5e38\u6570\u53d8\u91cf\uff1a<code>carry<\/code>,\u00a0<code>dummy<\/code>,\u00a0<code>p<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>\ud83e\udde9 \u89e3\u9898\u601d\u8def<\/p>\n\n\n\n<p>\u6838\u5fc3\u601d\u60f3\uff1a\u6a21\u62df\u5c0f\u5b66\u7ad6\u5f0f\u52a0\u6cd5\uff0c\u4ece\u4f4e\u4f4d\u5230\u9ad8\u4f4d\u9010\u4f4d\u76f8\u52a0\uff0c\u5904\u7406\u8fdb\u4f4d\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u521d\u59cb\u5316\uff1a\n<ul class=\"wp-block-list\">\n<li>\u521b\u5efa\u865a\u62df\u5934\u8282\u70b9\u00a0<code>dummy<\/code>\uff0c\u7b80\u5316\u94fe\u8868\u6784\u5efa\u3002<\/li>\n\n\n\n<li>\u6307\u9488\u00a0<code>p<\/code>\u00a0\u7528\u4e8e\u6784\u5efa\u7ed3\u679c\u94fe\u8868\u3002<\/li>\n\n\n\n<li><code>carry<\/code>\u00a0\u8bb0\u5f55\u8fdb\u4f4d\uff0c\u521d\u59cb\u4e3a 0\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u5faa\u73af\u6761\u4ef6\uff1a\n<ul class=\"wp-block-list\">\n<li><code>l1 != null<\/code>\u00a0\u6216\u00a0<code>l2 != null<\/code>\u00a0\u6216\u00a0<code>carry != 0<\/code><\/li>\n\n\n\n<li>\u5373\u4f7f\u4e24\u4e2a\u94fe\u8868\u90fd\u8d70\u5b8c\uff0c\u82e5\u8fd8\u6709\u8fdb\u4f4d\uff08\u5982 9+9=18\uff09\uff0c\u4ecd\u9700\u65b0\u589e\u8282\u70b9\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u6bcf\u8f6e\u64cd\u4f5c\uff1a\n<ul class=\"wp-block-list\">\n<li><code>sum = carry + (l1.val if exists) + (l2.val if exists)<\/code><\/li>\n\n\n\n<li>\u66f4\u65b0\u8fdb\u4f4d\uff1a<code>carry = sum \/ 10<\/code><\/li>\n\n\n\n<li>\u521b\u5efa\u65b0\u8282\u70b9\uff1a<code>sum % 10<\/code>\uff08\u5f53\u524d\u4f4d\u7ed3\u679c\uff09<\/li>\n\n\n\n<li>\u6307\u9488\u00a0<code>p<\/code>\u00a0\u524d\u79fb\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u8fd4\u56de\u7ed3\u679c\uff1a\n<ul class=\"wp-block-list\">\n<li><code>dummy.next<\/code>\u00a0\u5373\u4e3a\u7ed3\u679c\u94fe\u8868\u771f\u5b9e\u5934\u8282\u70b9\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p>\u4e3e\u4f8b\u8bf4\u660e\uff1a<\/p>\n\n\n\n<p>\u8f93\u5165\uff1a<code>l1 = [2,4,3]<\/code>, <code>l2 = [5,6,4]<\/code><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\u7b2c1\u4f4d\uff1a2 + 5 + 0 = 7 \u2192 carry=0 \u2192 \u8282\u70b9 7\n\u7b2c2\u4f4d\uff1a4 + 6 + 0 = 10 \u2192 carry=1 \u2192 \u8282\u70b9 0\n\u7b2c3\u4f4d\uff1a3 + 4 + 1 = 8 \u2192 carry=0 \u2192 \u8282\u70b9 8\n\u7ed3\u675f \u2192 \u7ed3\u679c\uff1a7\u21920\u21928 \u2705<\/code><\/pre>\n\n\n\n<p>\u8fb9\u754c\u5904\u7406\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e24\u4e2a\u94fe\u8868\u957f\u5ea6\u4e0d\u7b49 \u2192 \u77ed\u94fe\u8868\u8865 0\uff08\u4ee3\u7801\u4e2d\u901a\u8fc7 if \u5224\u65ad\u5b9e\u73b0\uff09\u3002<\/li>\n\n\n\n<li>\u6700\u540e\u4e00\u4f4d\u6709\u8fdb\u4f4d \u2192 \u5faa\u73af\u7ee7\u7eed\uff0c\u65b0\u589e\u8282\u70b9\uff08\u5982\u793a\u4f8b3\u672b\u5c3e\u7684 1\uff09\u3002<\/li>\n\n\n\n<li>\u5168\u4e3a 0 \u2192 \u76f4\u63a5\u8fd4\u56de [0]\uff08\u793a\u4f8b2\uff09\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\ud83d\udd17 \u4e24\u6570\u76f8\u52a0 \u9898\u76ee\u6765\u6e90\uff1a2. \u4e24\u6570\u76f8\u52a0 &#8211; \u529b\u6263\uff08LeetCode\uff09 \ud83d\udccc \u9898\u76ee\u63cf\u8ff0 \u7ed9\u4f60\u4e24\u4e2a\u975e\u7a7a\u7684 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,38],"tags":[34,14,51],"class_list":["post-377","post","type-post","status-publish","format-standard","hentry","category-algorithm","category-linked_list","tag-mathematics","tag-algorithm","tag-linked_list"],"_links":{"self":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/377","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=377"}],"version-history":[{"count":2,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/377\/revisions"}],"predecessor-version":[{"id":381,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/377\/revisions\/381"}],"wp:attachment":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/media?parent=377"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/categories?post=377"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/tags?post=377"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}