POJ1258 最小生成树prim算法

 典型的prim算法

这类题目可以稍作变形，比如POJ2421

#include <iostream> #include <map> #define MAXN 102 typedef long elem_t; using namespace std; elem_t prim(int n,elem_t mat[MAXN][MAXN]){ elem_t closeEdge[MAXN],sum=0,min; int i,j,k; for(i = 0; i < n; i++) closeEdge[i] = mat[0][i];//初始化辅助数组 for(i = 1; i < n; i++) { j = 0; while(!closeEdge[j])j++;//寻找第一个未归入的点 min = closeEdge[j];k = j; //开始寻找下一节点 for(j++; j < n; j++) if(closeEdge[j] && min > closeEdge[j]) { min = closeEdge[j]; k = j; } sum += closeEdge[k]; closeEdge[k] = 0; for(j = 0; j < n; j++)//新顶点入集并重新选择最小边 if(mat[k][j] && mat[k][j] < closeEdge[j]) closeEdge[j] = mat[k][j]; } return sum; } int main(){ int n,i,j; long result; long distance[MAXN][MAXN]; while(cin>>n){ for (i = 0;i < n;i++) for (j = 0;j < n;j++){ cin>>distance[i][j]; } result = prim(n,distance); cout<<result<<endl; } return 0; }