POJ 1502 MPI Maelstrom

#include <iostream>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
#define INF 0xfffffff
#define maxn 1006
#define min(a,b) (a<b?a:b)
#define max(a,b) (a>b?a:b)
int n;
int maps[maxn][maxn], dist[maxn];
bool vis[maxn];

int Dijkstra()
{
    dist[1] = 0;
    for(int i=1; i<=n; i++)
    {
        int index, Min = INF;

        for(int j=1; j<=n; j++)
        {
            if(!vis[j]  && Min > dist[j])
                index = j, Min = dist[j];
        }

        vis[index] = true;

        for(int j=1; j<=n; j++)
        {
            if( !vis[j] )
                dist[j] = min(dist[j], dist[index] + maps[index][j]);
        }
    }
    int Max = 0;
    for(int i=2; i<=n; i++)
        Max = max(Max, dist[i]);

    return Max;
}
void ReadMaps()
{
    char str[30];

    memset(vis,false,sizeof(vis));

    for(int i=1; i<=n; i++)
    {
        dist[i] = INF;
        maps[i][i] = 0;
        for(int j=1; j<i; j++)
        {
            scanf("%s", str);

            if(strcmp(str,"x") == 0)
                maps[i][j] = INF;
            else
                sscanf(str,"%d", &maps[i][j]);

            maps[j][i] = maps[i][j];
        }
    }
}
int main()
{
    while(cin >> n)
    {
        ReadMaps();

        int ans = Dijkstra();

        cout << ans << endl;
    }
    return 0;
}