题目连接:http://www.lightoj.com/volume_showproblem.php?problem=1040
题意也不说了。
水题
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <string>
#include <algorithm>
#include <math.h>
#include <ctype.h>
#include <time.h>
#include <queue>
#include <iterator>
#include <vector>
#include <set>
using namespace std;
const int MAXN = 55;
const int inf = 100000000;
int p[MAXN][MAXN];
int n;
int dis[MAXN], v[MAXN];
int prim(int map[][55], int n)
{
memset(v, 0, sizeof(v));
int min, sum = 0;
for (int i = 0; i < n; i++)
dis[i] = map[0][i];
v[0] = 1;
for (int i = 1; i < n; i++)
{
int k = -1;
min = inf;
for (int j = 0; j < n; j++)
if (!v[j] && min>dis[j])
{
k = j;
min = dis[j];
}
if (k == -1)
return - 1;
sum += min;
v[k] = 1;
for (int j = 0; j < n; j++)
if (!v[j] && dis[j]>map[k][j])
dis[j] = map[k][j];
}
return sum;
}
void init()
{
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
if (i != j && p[i][j] == 0 && p[j][i] == 0)
{
p[i][j] = p[j][i] = inf;
}
}
}
}
int main()
{
int t;
scanf("%d",&t);
for (int cases = 1; cases <= t; cases++)
{
int ans = 0;
memset(p,0,sizeof(p));
scanf("%d",&n);
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
{
scanf("%d",&p[i][j]);
ans += p[i][j];
if (i == j)
p[i][i] = 0;
if (i!=j && p[i][j] == 0)
{
p[i][j] = p[j][i];
}
else if (i != j && p[j][i] != 0 && p[i][j]!=0)
{
p[i][j] = p[j][i] = min(p[i][j], p[j][i]);
}
else if (i != j && p[j][i] == 0)
{
p[j][i] = p[i][j];
}
}
init();
int tmp = prim(p, n);
ans -= tmp;
if (tmp!=-1)
printf("Case %d: %d\n",cases,ans);
else
printf("Case %d: -1\n", cases);
}
return 0;
}