poj 1258 prim

//这题很简单//最小生成树用prim//就是求生成树边长之和#include <iostream>#include <cstring>#define MAXN 101#define INF 100001using namespace std;int N;int Edge[MAXN][MAXN];int lowcost[MAXN];int sumlen;void prim(){  lowcost[0] = -1;  int v;  for(int i = 1; i < N; i++)    {      lowcost[i] = Edge[0][i];    }  for(int i = 1; i < N; i++)    {      int min = INF;      for(int k = 1; k < N; k++){  if(lowcost[k] != -1 && lowcost[k] < min)    {      v = k;      min = lowcost[k];    }}      sumlen += min;      lowcost[v] = -1;      for(int k = 0; k < N; k++){  if(lowcost[k] > Edge[v][k])    {      lowcost[k] = Edge[v][k];    }}    }}int main(){  while(cin>>N)    {      if(N == 0)break;      for(int i = 0; i < N; i++){  for(int j = 0; j < N; j++)    {      cin>>Edge[i][j];    }}      memset(lowcost,0,sizeof(lowcost));      sumlen = 0;      prim();      cout<<sumlen<<endl;    }  return 0;}