最小生成树-Prim算法

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【问题】

求一个给定的加权连通图的最小生成树问题。

【代码】

#include <stdio.h>#include <stdlib.h>#define MAXNUM 1000#define MAX_VERTEX_NUM 20typedef char Vertextype;typedef struct node  {int weight;}Adjmatrix[MAX_VERTEX_NUM][MAX_VERTEX_NUM];typedef struct {Vertextype vexs[MAX_VERTEX_NUM];Adjmatrix arcs;int vexnum, arcnum;}Algraph;typedef struct{int start_vex;int end_vex;int weight;}Edge;void prim(Algraph G, int firstvex){Edge E[MAXNUM];Edge tmp;int vex_num;int m, t, w;int min = MAXNUM, i = 0, j = 0, k = 0;vex_num = G.vexnum;//初始化Edgefor(i = 0; i < vex_num; i++){E[i].start_vex = firstvex;if(i >= firstvex){E[i].end_vex = i + 1;E[i].weight = G.arcs[firstvex][i+1].weight;}else{E[i].end_vex = i;E[i].weight = G.arcs[firstvex][i].weight;}}//对所有的顶点依次处理for(i = 1; i < vex_num; i++){min = MAXNUM;    m = i - 1;//找出当前顶点的最小权重边for(j = i - 1; j < vex_num - 1; j++){if(E[j].weight < min){min = E[j].weight;m = j;}}//依次将处理完的顶点放到前端tmp = E[i - 1];E[i - 1] = E[m];E[m] = tmp;j = E[i - 1].end_vex;//更新权重for(k = i; k < vex_num - 1; k++){t = E[k].end_vex;w = G.arcs[j][t].weight;if(w < E[k].weight){E[k].weight = w;E[k].start_vex = j;}}}}

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