POJ-2387 Til the Cows Come Home

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int maxn = 1005;
const int INF = 99999;
int graph[maxn][maxn];
int root[maxn];
int sign[maxn];
int t, n, ans;

void Dijkstra()
{
ans = 0;
memset(sign, 0, sizeof(sign));
for(int i = 1; i <= n; i ++)
root[i] = graph[1][i];
sign[1] = 1;
for(int cnt = 2; cnt <= n; cnt ++)
{
int min_num = INF;
int minn = 1;
for(int i = 1; i <= n; i ++)
if(!sign[i] && root[i] < min_num)
{
min_num = root[i];
minn = i;
}
sign[minn] = 1;
if(min_num == INF)
break;
for(int i = 1; i <= n; i ++)
root[i] = min(root[minn] + graph[minn][i], root[i]);
}
}

int main()
{
while(~scanf("%d %d", & t, & n))
{
for(int i = 1; i <= n; i ++)
for(int j = 1; j <= n; j ++)
graph[i][j] = INF;
while(t --)
{
int a, b, c;
scanf("%d %d %d", & a, & b, & c);
if(c < graph[a][b])
graph[a][b] = graph[b][a] = c;
}
Dijkstra();
printf("%d\n", root
);
}
return 0;
}