07 2017 档案

the shortest path algorithm

摘要：Dijkstra算法 又称迪杰斯特拉算法，是一个经典的最短路径算法，主要特点是以起始点为中心向外层层扩展，直到扩展到终点为止，使用了广度优先搜索解决赋权有向图的单源最短路径问题，算法最终得到一个最短路径树。时间复杂度为O(N^2) 执行动画： 实例： 抽象步骤： 1.将起点A放入集合中，A点的权值为 阅读全文

posted @ 2017-07-17 11:20 Wujunde 阅读(134) 评论(0) 推荐(0)

Minimum Spanning Trees

摘要：Kruskal’s algorithm always union the lightest link if two sets haven't been linked Prim’s algorithm maintain a key of each vertex to represent the lig 阅读全文

posted @ 2017-07-13 16:15 Wujunde 阅读(153) 评论(0) 推荐(0)

Strongly connected components

摘要：拓扑排列可以指明除了循环以外的所有指向，当反过来还有路可以走的话，说明有刚刚没算的循环路线，所以反过来能形成的所有树都是循环 阅读全文

posted @ 2017-07-10 22:13 Wujunde 阅读(296) 评论(0) 推荐(0)

topological sort

摘要：A topological sortof a dag G is a linear ordering of all its vertices such that if G contains anedge(u,v) then u appears before  in the ordering. (If 阅读全文

posted @ 2017-07-10 21:34 Wujunde 阅读(137) 评论(0) 推荐(0)

depth first search

摘要：Besides creating a depth-first forest, depth-first search also timestamps each vertex.Each vertex  has two timestamps: the first timestamp :d record 阅读全文

posted @ 2017-07-10 21:16 Wujunde 阅读(323) 评论(0) 推荐(0)

Breadth-first search

摘要：given a graph G and a distinguished source vertex s, breadth-firstsearch systematically explores the edges of G to “discover” every vertex that isreac 阅读全文

posted @ 2017-07-07 22:04 Wujunde 阅读(165) 评论(0) 推荐(0)

Representations of graphs

摘要：We can choose between two standard ways to represent a graph as a collection of adjacency lists or as an adjacency matrix. Either way appliesto both d 阅读全文

posted @ 2017-07-07 22:00 Wujunde 阅读(200) 评论(0) 推荐(0)

disjoint set

摘要：MAKE-SET.x/ creates a new set whose only member (and thus representative) is x. Since the sets are disjoint, we require that x not already be in some 阅读全文

posted @ 2017-07-06 16:17 Wujunde 阅读(426) 评论(0) 推荐(0)