Bellman-ford \u7b97\u6cd5\u6bd4dijkstra\u7b97\u6cd5\u66f4\u5177\u666e\u904d\u6027\uff0c\u56e0\u4e3a\u5b83\u5bf9\u8fb9\u6ca1\u6709\u8981\u6c42\uff0c\u53ef\u4ee5\u5904\u7406\u8d1f\u6743\u8fb9\u4e0e\u8d1f\u6743\u56de\u8def\u3002\u7f3a\u70b9\u662f\u65f6\u95f4\u590d\u6742\u5ea6\u8fc7\u9ad8\uff0c\u9ad8\u8fbeO(VE), V\u4e3a\u9876\u70b9\u6570\uff0cE\u4e3a\u8fb9\u6570\u3002<\/p>\n\n\n\n
\u7279\u70b9\uff1a\u652f\u6301\u6709\u73af\uff0c\u8d1f\u6743\u91cd\uff0c\u4f46\u4e0d\u80fd\u5b58\u5728\u8d1f\u6743\u91cd\u73af<\/strong>\u3002<\/p>\n\n\n\n \u5176\u4e3b\u8981\u601d\u60f3\uff1a\u5bf9\u6240\u6709\u7684\u8fb9\u8fdb\u884cn-1\u8f6e\u677e\u5f1b\u64cd\u4f5c\uff0c\u56e0\u4e3a\u5728\u4e00\u4e2a\u542b\u6709n\u4e2a\u9876\u70b9\u7684\u56fe\u4e2d\uff0c\u4efb\u610f\u4e24\u70b9\u4e4b\u95f4\u7684\u6700\u77ed\u8def\u5f84\u6700\u591a\u5305\u542bn-1\u8fb9\u3002\u6362\u53e5\u8bdd\u8bf4\uff0c\u7b2c1\u8f6e\u5728\u5bf9\u6240\u6709\u7684\u8fb9\u8fdb\u884c\u677e\u5f1b\u540e\uff0c\u5f97\u5230\u7684\u662f\u6e90\u70b9\u6700\u591a\u7ecf\u8fc7\u4e00\u6761\u8fb9\u5230\u8fbe\u5176\u4ed6\u9876\u70b9\u7684\u6700\u77ed\u8ddd\u79bb\uff1b\u7b2c2\u8f6e\u5728\u5bf9\u6240\u6709\u7684\u8fb9\u8fdb\u884c\u677e\u5f1b\u540e\uff0c\u5f97\u5230\u7684\u662f\u6e90\u70b9\u6700\u591a\u7ecf\u8fc7\u4e24\u6761\u8fb9\u5230\u8fbe\u5176\u4ed6\u9876\u70b9\u7684\u6700\u77ed\u8ddd\u79bb\uff1b\u7b2c3\u8f6e\u5728\u5bf9\u6240\u6709\u7684\u8fb9\u8fdb\u884c\u677e\u5f1b\u540e\uff0c\u5f97\u5230\u7684\u662f\u6e90\u70b9\u6700\u591a\u7ecf\u8fc7\u4e00\u6761\u8fb9\u5230\u8fbe\u5176\u4ed6\u9876\u70b9\u7684\u6700\u77ed\u8ddd\u79bb……<\/p>\n\n\n\n Bellman-Ford \u7b97\u6cd5\u63cf\u8ff0\uff1a<\/p>\n\n\n\n \u5176\u4e2d\uff0c n\u4e3a\u9876\u70b9\u7684\u4e2a\u6570\uff0cm\u4e3a\u8fb9\u7684\u4e2a\u6570\uff0cedges\u6570\u7ec4\u50a8\u5b58\u4e86\u6240\u6709\u8fb9\uff0cdistance\u6570\u7ec4\u662f\u6e90\u70b9\u5230\u6240\u6709\u70b9\u7684\u8ddd\u79bb\u4f30\u8ba1\u503c\uff0c\u5faa\u73af\u7ed3\u675f\u540e\u5c31\u662f\u6700\u5c0f\u503c\u3002<\/p>\n\n\n\n \u7b97\u6cd5\u8fc7\u7a0b\uff1a\u9996\u5148\u521d\u59cb\u5316\uff0c\u5bf9\u6240\u6709\u7684\u8282\u70b9V\u6765\u8bf4\uff0c\u6240\u6709\u7684\u8fb9E\u8fdb\u884c\u677e\u5f1b\u64cd\u4f5c\uff0c\u518d\u7136\u540e\u5faa\u73af\u904d\u5386<\/a>\u6bcf\u6761\u8fb9\uff0c\u5982\u679cd[v] > d[u] + w(u,v),\u8868\u793a\u6709\u4e00\u4e2a\u8d1f\u6743\u91cd\u7684\u73af\u8def\u5b58\u5728\u3002<\/p>\n\n\n\n \u00a0\u6700\u540e\u5982\u679c\u6ca1\u6709\u8d1f\u6743\u91cd\u73af\u8def\uff0c\u90a3\u4e48d[v] \u662f\u6700\u5c0f\u8def\u5f84\u503c\u3002<\/p>\n\n\n\n python \u5b9e\u73b0\uff1a<\/p>\n\n\n\n Bellman-ford \u7b97\u6cd5\u6bd4dijkstra\u7b97\u6cd5\u66f4\u5177\u666e\u904d\u6027\uff0c\u56e0\u4e3a\u5b83\u5bf9\u8fb9\u6ca1\u6709\u8981\u6c42\uff0c\u53ef\u4ee5\u5904\u7406\u8d1f\u6743\u8fb9\u4e0e\u8d1f\u6743\u56de\u8def\u3002 … \u7ee7\u7eed\u9605\u8bfbBellman-Ford \u5355\u6e90\u6700\u77ed\u8def\u5f84\uff08\u56de\u8def\uff09\u7b97\u6cd5<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6,8],"tags":[],"_links":{"self":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/2983"}],"collection":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/comments?post=2983"}],"version-history":[{"count":8,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/2983\/revisions"}],"predecessor-version":[{"id":3023,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/2983\/revisions\/3023"}],"wp:attachment":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/media?parent=2983"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/categories?post=2983"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/tags?post=2983"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}for (var i = 0; i < n - 1; i++) {\r\n for (var j = 0; j < m; j++) {\/\/\u5bf9m\u6761\u8fb9\u8fdb\u884c\u5faa\u73af\r\n var edge = edges[j];\r\n \/\/ \u677e\u5f1b\u64cd\u4f5c\r\n if (distance[edge.to] > distance[edge.from] + edge.weight ){ \r\n distance[edge.to] = distance[edge.from] + edge.weight;\r\n }\r\n }\r\n}<\/code><\/pre>\n\n\n\n\r\ndef bellman_ford(graph, source):\r\n dist = {}\r\n p = {}\r\n max = 10000\r\n for v in graph:\r\n dist[v] = max #\u8d4b\u503c\u4e3a\u8d1f\u65e0\u7a77\u5b8c\u6210\u521d\u59cb\u5316\r\n p[v] = None\r\n dist[source] = 0\r\n \r\n for i in range(len( graph ) - 1):\r\n for u in graph:\r\n for v in graph[u]:\r\n if dist[v] > graph[u][v] + dist[u]:\r\n dist[v] = graph[u][v] + dist[u]\r\n p[v] = u #\u5b8c\u6210\u677e\u5f1b\u64cd\u4f5c\uff0cp\u4e3a\u524d\u9a71\u8282\u70b9\r\n \r\n for u in graph:\r\n for v in graph[u]:\r\n if dist[v] > dist[u] + graph[u][v]:\r\n return None, None #\u5224\u65ad\u662f\u5426\u5b58\u5728\u73af\u8def\r\n \r\n return dist, p\r\n \r\ndef test():\r\n graph = {\r\n 'a': {'b': -1, 'c': 4},\r\n 'b': {'c': 2, 'd': 3, 'e': 2},\r\n 'c': {},\r\n 'd': {'b': 3, 'c': 5},\r\n 'e': {'d': -3}\r\n }\r\n dist, p = bellman_ford(graph, 'a')\r\n print(dist)\r\n print(p)\r\ndef testfail():\r\n graph = {\r\n 'a': {'b': -1, 'c': 4},\r\n 'b': {'c': 2, 'd': 3, 'e': 2},\r\n 'c': {'d': -5},\r\n 'd': {'b': 3},\r\n 'e': {'d': -3}\r\n }\r\n dist, p = bellman_ford(graph, 'a')\r\n print(dist)\r\n print(p)\r\n \r\ntest()\r\ntestfail()<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"