pku 2485 Highways 典型最小生成树

题目连接

http://acm.pku.edu.cn/JudgeOnline/problem?id=2485

典型最小生成树





#include <stdio.h>

#define MAX_V 501
int arc[MAX_V][MAX_V];

int N;
struct CloseEdge{
int adjvex;
int lowcost;
}closedge[MAX_V];

int longest;

void MiniSpanTree_PRIM(int u){
longest = 0;
//初始化辅助数组
int i,j,k;
for(i = 0;i < N;i++)
if(i != u){
closedge[i].adjvex = u;
closedge[i].lowcost = arc[u][i];
}
//初始,U = {u}
closedge[u].lowcost = 0;
//选择其余N - 1个顶点
for(i = 0;i < N - 1;i++){
//求出最小生成树的下一个节点,第k顶点
int MaxCost = 1 << 20;
for(j = 0; j < N;j++)
if(closedge[j].lowcost != 0 && MaxCost > closedge[j].lowcost)
{
MaxCost = closedge[j].lowcost;
k = j;
}
if(longest < closedge[k].lowcost)
longest = closedge[k].lowcost;
//k顶点加入到U集
closedge[k].lowcost = 0;
//新节点添加到树后,修改closedge数组
for(j = 0;j < N;j++)
if(closedge[j].lowcost > arc[k][j]){
closedge[j].adjvex = k;
closedge[j].lowcost = arc[k][j];
}
}
}

int main(){
//FILE *fp = fopen("data.txt","r");
int test;
//fscanf(fp,"%d",&test);
scanf("%d",&test);
while(test--){
//fscanf(fp,"%d",&N);
scanf("%d",&N);
for(int i = 0;i < N;i++)
for(int j = 0;j < N;j++)
//fscanf(fp,"%d",&arc[i][j]);
scanf("%d",&arc[i][j]);
MiniSpanTree_PRIM(0);
printf("%d/n",longest);
}
return 0;
}