{"id":138,"date":"2025-10-10T11:27:56","date_gmt":"2025-10-10T03:27:56","guid":{"rendered":"http:\/\/4.189.252.43\/?p=138"},"modified":"2025-10-11T00:43:19","modified_gmt":"2025-10-10T16:43:19","slug":"%e6%9c%89%e4%bf%a1%e6%81%af%e6%90%9c%e7%b4%a2","status":"publish","type":"post","link":"http:\/\/4.189.252.43\/index.php\/2025\/10\/10\/%e6%9c%89%e4%bf%a1%e6%81%af%e6%90%9c%e7%b4%a2\/","title":{"rendered":"\u6709\u4fe1\u606f\u641c\u7d22"},"content":{"rendered":"\n<p>\u53c8\u540d\u201c\u542f\u53d1\u5f0f\u641c\u7d22\u201d<\/p>\n\n\n\n<p>\u542f\u53d1\u5f0f\u4fe1\u606f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f30\u8ba1\u79bb\u76ee\u6807\u72b6\u6001\u6709\u591a\u8fdc\u7684\u4fe1\u606f<\/li>\n\n\n\n<li>\u4e0d\u540c\u7684\u95ee\u9898\u9700\u8981\u8bbe\u8ba1\u4e0d\u540c\u7684\u542f\u53d1\u4fe1\u606f<\/li>\n\n\n\n<li>\u4f8b\u5982\uff1a\u66fc\u54c8\u987f\u8ddd\u79bb\u3001\u6b27\u5f0f\u8ddd\u79bb<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e00\u3001 \u8d2a\u5a6a\u641c\u7d22(greedy search)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u8d2a\u5a6a\u7b97\u6cd5(greedy algorithm)<\/h3>\n\n\n\n<p>\u53c8\u79f0\u8d2a\u5fc3\u7b97\u6cd5\uff0c\u6307\u5728\u6bcf\u4e00\u6b65\u9009\u62e9\u4e2d\u90fd\u91c7\u53d6\u5728\u5f53\u524d\u72b6\u6001\u4e0b\u6700\u597d\u6216\u6700\u4f18\uff08\u5373\u6700\u6709\u5229\uff09\u7684\u9009\u62e9\uff0c\u4ece\u800c\u5e0c\u671b\u5bfc\u81f4\u7ed3\u679c\u662f\u6700\u597d\u6216\u6700\u4f18\u7684\u7b97\u6cd5\u3002<\/p>\n\n\n\n<p>\u6ca1\u6709\u4ece\u603b\u4f53\u4e0a\u8003\u8651\u5176\u4ed6\u53ef\u80fd\u60c5\u51b5\uff0c\u6bcf\u6b21\u9009\u53d6\u5c40\u90e8\u6700\u4f18\u89e3\uff0c\u4e00\u822c\u4e0d\u80fd\u5f97\u5230\u6700\u4f18\u89e3\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u6982\u5ff5<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b56\u7565\uff1a\u6bcf\u4e00\u6b65\u5747\u6269\u5c55\u8ddd\u79bb\u76ee\u6807\u72b6\u6001\u66f4\u8fd1\u7684\u8282\u70b9\u3002 \u542f\u53d1\u5f0f\u4fe1\u606f\uff1a\u4f30\u8ba1\u5f53\u524d\u72b6\u6001\u8ddd\u79bb\u76ee\u6807\u72b6\u6001\u7684\u8ddd\u79bb<\/li>\n\n\n\n<li>Common case\uff1a \u8ddd\u79bb\u76ee\u6807\u8d8a\u6765\u8d8a\u8fd1<\/li>\n\n\n\n<li>Bad case: \u975e\u5b8c\u5907\u3001\u975e\u6700\u4f18\u3001\u4f9d\u8d56\u542f\u53d1\u5f0f\u51fd\u6570<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001 A*\u641c\u7d22<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u6982\u5ff5\uff1a<\/h3>\n\n\n\n<p>$$<br>f(n) = g(n) + h(n)<br>$$<\/p>\n\n\n\n<p>$g(n)$\u8868\u793a\u4ece\u8d77\u59cb\u8282\u70b9\u5230\u8282\u70b9$n$\u7684\u5f00\u9500\u4ee3\u4ef7\u503c\uff0c$h(n)$\u8868\u793a\u4ece\u8282\u70b9$n$\u5230\u76ee\u6807\u8282\u70b9\u8def\u5f84\u4e2d\u6240\u4f30\u7b97\u7684\u6700\u5c0f\u5f00\u9500\u4ee3\u4ef7\u503c\u3002<\/p>\n\n\n\n<p><strong>\u8bc4\u4ef7\u51fd\u6570<\/strong>$f(n)$\u53ef\u89c6\u4e3a\u7ecf\u8fc7\u8282\u70b9$n$\u3001\u5177\u6709\u6700\u5c0f\u5f00\u9500\u4ee3\u4ef7\u503c\u7684\u8def\u5f84\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2*. A*\u7b97\u6cd5\u7684\u5b8c\u5907\u6027<\/h3>\n\n\n\n<p>\u5728\u4e00\u4e9b\u5e38\u89c1\u7684\u641c\u7d22\u95ee\u9898\u4e2d\uff0c\u72b6\u6001\u6570\u91cf\u662f\u6709\u9650\u7684\uff0c\u6b64\u65f6\u56fe\u641c\u7d22A*\u7b97\u6cd5\u548c\u6392\u9664\u73af\u8def\u7684\u6811\u641c\u7d22A*\u7b97\u6cd5\u5747\u662f\u5b8c\u5907\u7684\u3002<\/p>\n\n\n\n<p>\u5728\u66f4\u666e\u904d\u7684\u60c5\u51b5\u4e0b\uff0c\u5982\u679c\u6240\u6c42\u95ee\u9898\u548c\u542f\u53d1\u5f0f\u51fd\u6570\u6ee1\u8db3\u4ee5\u4e0b\u6761\u4ef6\uff0c\u5219A*\u7b97\u6cd5\u662f\u5b8c\u5907\u7684\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u641c\u7d22\u6811\u4e2d\u5206\u652f\u6570\u91cf\u662f\u6709\u9650\u7684\uff0c\u5373\u6bcf\u4e2a\u8282\u70b9\u7684\u540e\u7ee7\u8282\u70b9\u6570\u91cf\u662f\u6709\u9650\u7684\u3002<\/li>\n\n\n\n<li>\u5355\u6b65\u4ee3\u4ef7\u7684\u4e0b\u754c\u662f\u4e00\u4e2a\u6b63\u6570<\/li>\n\n\n\n<li>\u542f\u53d1\u51fd\u6570\u6709\u4e0b\u754c<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">3*. A*\u7b97\u6cd5\u7684\u6700\u4f18\u6027<\/h3>\n\n\n\n<p>\u5982\u4f55\u4fee\u6539\u542f\u53d1\u5f0f\u4fe1\u606f\u53ef\u4ee5\u4f7f\u7b97\u6cd5\u627e\u5230\u6700\u4f18\u89e3\uff1f<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u53ef\u91c7\u7eb3\u6027(admissible)\uff1a\u5bf9\u4e8e\u4efb\u610f\u8282\u70b9$n$\uff0c\u6709$h(n) \\leq h^*(n)$ \u542f\u53d1\u5f0f\u51fd\u6570\u4e0d\u4f1a\u8fc7\u9ad8\u4f30\u8ba1\u4ece\u8282\u70b9$n$\u5230\u7ec8\u6b62\u8282\u70b9\u6240\u5e94\u8be5\u4ed8\u51fa\u7684\u4ee3\u4ef7\u3002\uff08\u4f30\u8ba1\u4ee3\u4ef7\u5c0f\u4e8e\u7b49\u4e8e\u5b9e\u9645\u4ee3\u4ef7\uff09<\/li>\n\n\n\n<li>\u4e00\u81f4\u6027\uff1a\u5bf9\u4e8e\u6bcf\u4e2a\u8282\u70b9$n$\u548c\u901a\u8fc7\u4efb\u4e00\u884c\u52a8$a$\u751f\u6210\u7684$n$\u7684\u6bcf\u4e2a\u540e\u7ee7\u8282\u70b9$n&#8217;$\uff0c\u6709$h(n) \\leq cost(n, a, n&#8217;) + h(n&#8217;)$<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u4ee3\u7801<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>def A_star(heuristic):\n    Frontier = priority_queue()\n    Frontier.push((start_state, &#91;]), 0 + heuristic(start_state))\n\n    visited = {}\n\n    while Frontier.isEmpty() == 0:\n        state, actions = Frontier.pop()\n        if state in visited and get_cost_of_actions(state) + heurisitc(state) &gt;= visited&#91;state]:\n            continue\n        visited&#91;state] = get_cost_of_actions(state) + heurisitc(state)\n        if is_target_state(state):\n            return actions\n        for next_state, next_direction in get_successors(state):\n            Frontier.push((next_state, actions + &#91;next_direction]), get_cost_of_actions(actions + &#91;next_direction] +heuristic(next_state)))\n     return None<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u3001 \u542f\u53d1\u5f0f\u51fd\u6570\uff08heuristic function\uff09<\/h2>\n\n\n\n<p>\u542f\u53d1\u5f0f\u641c\u7d22\u7684\u5173\u952e\u5728\u4e8e\u5982\u4f55\u8bbe\u8ba1\u542f\u53d1\u5f0f\u51fd\u6570\u3002<\/p>\n\n\n\n<p>\u53ef\u91c7\u7eb3\u7684\u542f\u53d1\u5f0f\u51fd\u6570\u53ef\u4ee5\u770b\u505a\u677e\u5f1b\u95ee\u9898(relaxed problems)\u7684\u89e3\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u4f8b\u5b50\uff1a\u516b\u6570\u7801\u95ee\u9898<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u4e0d\u5728\u6b63\u786e\u4f4d\u7f6e\u7684\u68cb\u5b50\u6570\u3002<\/li>\n\n\n\n<li>\u6240\u6709\u68cb\u5b50\u5230\u76ee\u6807\u4f4d\u7f6e\u7684\u8ddd\u79bb\u548c\uff08\u66fc\u54c8\u987f\u8ddd\u79bb\uff09<\/li>\n<\/ol>\n\n\n\n<p>\u5982\u679c\u542f\u53d1\u5f0f\u51fd\u6570\\(h(n) = 0\\) \\(\\Rightarrow\\) \u7b49\u4ef7\u4e8e\u4e00\u81f4\u6027\u4ee3\u4ef7\u641c\u7d22<\/p>\n\n\n\n<p>\u5982\u679c\u91c7\u7528\u771f\u5b9e\u7684\u4ee3\u4ef7\u4f5c\u4e3a\u542f\u53d1\u5f0f\u51fd\u6570 $\\Rightarrow$ \u6700\u4f73\u60c5\u51b5\uff0c\u4f46\u662f\u4e0d\u53ef\u80fd\u5b9e\u73b0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u53c8\u540d\u201c\u542f\u53d1\u5f0f\u641c\u7d22\u201d \u542f\u53d1\u5f0f\u4fe1\u606f\uff1a \u4e00\u3001 \u8d2a\u5a6a\u641c\u7d22(greedy search) 1. \u8d2a\u5a6a\u7b97\u6cd5(greedy  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[21,4],"tags":[],"class_list":["post-138","post","type-post","status-publish","format-standard","hentry","category-21","category-4"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/posts\/138","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/comments?post=138"}],"version-history":[{"count":3,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/posts\/138\/revisions"}],"predecessor-version":[{"id":178,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/posts\/138\/revisions\/178"}],"wp:attachment":[{"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/media?parent=138"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/categories?post=138"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4.189.252.43\/index.php\/wp-json\/wp\/v2\/tags?post=138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}