\u6628\u5929\u6709\u4e2a\u4ee5\u524d\u4e00\u8d77\u73a9 ACM \u7684\u961f\u53cb\u8ddf\u6211\u8bf4\u4e2a\u9898, \u8bf4\u662f\u524d\u51e0\u5929\u817e\u8baf\u5b9e\u4e60\u751f\u62db\u8058\u7684\u7b14\u8bd5\u9898\u4e4b\u4e00, \u539f\u6587\u5982\u4e0b<\/p>\n
\u5df2\u77e5a[0],a[1]…a[n-1]
\n\u73b0\u5728\u8981\u6784\u9020b[0],b[1]…b[n-1]
\n\u5176\u4e2d b[i]=a[0]*a[1]*….a[n-1]\/a[i]
\n\u8981\u6c42\uff0c\u4e0d\u80fd\u7528\u9664\u6cd5\uff0c\u4e0d\u80fd\u4f7f\u7528\u5176\u4ed6\u4efb\u4f55\u5b58\u50a8\u53d8\u91cf\uff0c\u9664\u4e86\u5faa\u73af\u53d8\u91cfi,j\u4e4b\u7c7b\u7684
\n\u8981\u6c42O(1)\u7684\u7a7a\u95f4\u590d\u6742\u5ea6\uff0cO(n)\u7684\u65f6\u95f4\u590d\u6742\u5ea6 <\/p>\n\u5173\u952e\u662f\u4e0d\u80fd\u7528\u9664\u6cd5 <\/p><\/blockquote>\n
\u770b\u5230\u8fd9\u9898\u540e\u7684\u7b2c\u4e00\u53cd\u5e94\u662f\u8fd9\u7279\u4e48\u4e0d\u4f1a\u7206\u7c7b\u578b\u4e48? double \u4e5f\u7ecf\u4e0d\u8d77\u8fd9\u4e48\u641e\u5427. \u7136\u540e\u5c31\u51b7\u9759\u4e0b\u6765\u60f3\u600e\u4e48\u89e3\u51b3, \u4e0d\u80fd\u7528\u9664\u6cd5\u5c31\u907f\u5f00\u90a3\u4e2a\u9664\u6cd5\u64cd\u4f5c\u54af, \u628a b[i] \u7684\u63a8\u5bfc\u516c\u5f0f\u6362\u6210 a[0]*…*a[i-1]*a[i+1]*…*a[n-1] \u5c31\u662f\u4e86, \u4e00\u770b\u5c31\u50cf\u4e2a DP. \u63a8\u4e86\u4e0b\u540e\u5199\u4e86\u8fd9\u4e48\u4e2a\u4ee3\u7801 (\u5047\u8bbe\u6240\u6709\u6570\u90fd\u662f int \u4e14\u4e0d\u7206\u7c7b\u578b\u5927\u5c0f)<\/p>\n
\/\/ \u5148\u6784\u9020\u4e00\u904d, \u4f7f\u5f97 b[i] = a[0]*...*a[i-1]\nb[0] = 1;\nfor (int i = 1; i < n; ++i) {\n b[i] = b[i-1]*a[i-1];\n}\n\n\/\/ \u9006\u5e8f, \u4f7f\u5f97\u904d\u5386\u5230 b[i] \u65f6, sum = a[i+1]*...*a[n-1]\n\/\/\u8fd9\u65f6\u5019 b[i]*sum = a[0]*...*a[n-1]\/a[i]\nint sum = 1;\nfor (int i = n-1; i >= 0; --i) {\n b[i] *= sum;\n sum *= a[i];\n}<\/pre>\n\u7136\u540e\u88ab\u63d0\u9192\u8bf4 sum \u8fd9\u4e2a\u53d8\u91cf\u4e5f\u4e0d\u80fd\u6709, \u597d\u50cf\u539f\u6587\u4e2d\u662f\u8bf4\u4e86\u4e0d\u80fd\u7528\u5176\u4ed6\u5b58\u50a8\u53d8\u91cf… \u4f46\u662f\u8fd9\u4e0d\u8fd8\u662f O(1) \u7684\u7a7a\u95f4\u590d\u6742\u5ea6\u4e48, \u817e\u8baf\u597d\u50cf\u7ecf\u5e38\u559c\u6b22\u641e\u8fd9\u79cd\u65e0\u804a\u7684\u8981\u6c42 (\u5361\u4e00\u4e24\u4e2a\u53d8\u91cf), \u4e8e\u662f\u5f53\u573a\u5c31\u6012\u4e86<\/p>\n
\u53f6\u6587\/Snoopy\u963f\u6392 20:41:49
\n\u90a3\u628a\u4ed6\u5199\u5230\u5faa\u73af\u91cc\u597d\u4e86… -.-|
\n\u53f6\u6587\/Snoopy\u963f\u6392 20:42:32
\n\u8001\u5b9e\u8bf4, \u8fd9\u4e2a\u9898\u51fa\u7684\u5f88\u70c2…
\n\u53f6\u6587\/Snoopy\u963f\u6392 20:42:36
\n\u70c2\u7684\u65e0\u4e0e\u4f26\u6bd4
\n** 20:43:05
\n\u54c8\u54c8
\n\u53f6\u6587\/Snoopy\u963f\u6392 20:43:15
\n\u9996\u5148, \u8fd9\u79cd\u5947\u6280\u6deb\u5de7\u6ca1\u6709\u4efb\u4f55\u610f\u4e49
\n\u5176\u6b21, \u8fde\u4e58\u66f4\u5927\u7684\u95ee\u9898\u662f\u7206\u6570\u636e\u7c7b\u578b…
\n** 20:44:41
\n\u662f\u554a
\n** 20:44:51
\n\u5173\u952e\u4e00\u70b9\u5c31\u662f\u6ca1\u6709\u4efb\u4f55\u610f\u4e49
\n\u53f6\u6587\/Snoopy\u963f\u6392 20:45:41
\n\u800c\u4e14, \u8981\u771f\u62a0\u7ec6\u8282, \u4ed6\u6ca1\u8bf4\u4e0d\u80fd\u4fee\u6539 a \u7684\u503c, \u6211\u5728\u505a\u9006\u5e8f\u7684\u65f6\u5019\u628a sum \u6362\u6210 a[] \u5c31\u884c\u4e86<\/p><\/blockquote>\n\u679c\u7136\u6539 a \u6570\u7ec4\u7684\u503c\u5c31\u8fbe\u5230\u76ee\u7684\u4e86? \u597d\u50cf\u662f? \u8fd9\u6837\u6709\u610f\u601d\u4e48?<\/p>\n
\u6700\u540e, \u771f\u5fc3\u6c42\u65e2\u4e0d\u4f7f\u7528\u591a\u4f59\u53d8\u91cf, \u4e14\u4e0d\u4fee\u6539 a \u7684\u503c\u7684\u505a\u6cd5.<\/p>\n","protected":false},"excerpt":{"rendered":"
\u6628\u5929\u6709\u4e2a\u4ee5\u524d\u4e00\u8d77\u73a9 ACM \u7684\u961f\u53cb\u8ddf\u6211\u8bf4\u4e2a\u9898, \u8bf4\u662f\u524d\u51e0\u5929\u817e\u8baf\u5b9e\u4e60\u751f\u62db\u8058\u7684\u7b14\u8bd5\u9898\u4e4b\u4e00, \u539f\u6587\u5982\u4e0b \u5df2\u77e5a[0] […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[5,7],"tags":[58,385,398],"class_list":["post-1542","post","type-post","status-publish","format-standard","hentry","category-work-life","category-tech-notes","tag-dp","tag-385","tag-398"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4aR5e-oS","_links":{"self":[{"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/posts\/1542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/comments?post=1542"}],"version-history":[{"count":0,"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/posts\/1542\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/media?parent=1542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/categories?post=1542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.yewen.us\/blog\/wp-json\/wp\/v2\/tags?post=1542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}