Domino Effect ZOJ 1298 POJ 1135 Dijkstra

这题WA很久，然后找不出原因，后来看了书上的程序（图论理论算法实现及应用神马的），然后感觉不出来自己哪里错了，后来改了改，把无穷大的定义改小了点，再放到ZOJ上，成功AC了，我都不知道为什么，也许还改了其他地方，我已经糊涂了，然后又把它放POJ 1135上又WA了，我都憔悴了，最后我想起以前刷水题时要把double用%f输出，我试了一下，果然AC了，求解释`````

贴代码：

#include <cstdio>
#include <cstring>
#define MAXN 505
#define INF 1000000
int n;
int edge[MAXN][MAXN];
bool s[MAXN];
int time[MAXN];
void Dijkstra()
{
    int i,j;
    for(i=1; i<=n; i++)
        time[i] = edge[1][i];
    memset(s,false,sizeof(s));
    s[1] = true;
    for(i=1; i<n; i++)
    {
        int min = 1000000;
        int v = 1 ;
        for(j = 1; j<=n; j++)
        {
            if(!s[j] &&time[j] < min)
            {
                min = time[j];
                v = j;
            }
        }
        s[v] = true;//表明v算过了
        for(j=1; j<=n ; j++)
        {
            if(!s[j] && edge[v][j] < INF && time[v] + edge[v][j] < time[j])//该点没被算过，v到j有边存在，距离更短
                time[j] = time[v] + edge[v][j] ;
        }
    }
    double max1 = -1;
    int po;
    time[1] = 0;
    for(i=1; i<=n; i++)
    {
        if(time[i] > max1)
        {
            max1 = time[i];
            po = i;
        }
    }
    double max2 = -1;
    int pox,poy;
    for(i=1; i<=n; i++)
    {
        for(j=1; j<=n; j++)
        {
            int t;
            if(edge[i][j] == INF) continue;
            double temp = (time[i] + time[j] + edge[i][j])/2.0 ;
            if(temp > max2 )
            {
                max2 = temp;
                pox = i;
                poy = j;
            }
        }
    }
    if(max2 > max1)
    {
        printf("The last domino falls after %.1f seconds, between key dominoes %d and %d.\n\n",max2,pox,poy);
    }
    else
    {
        printf("The last domino falls after %.1f seconds, at key domino %d.\n\n",max1,po);
    }
}
int main()
{
//    freopen("in.cpp","r",stdin);
    int m;
    int ser  = 0;
    while(~scanf("%d%d",&n,&m))
    {
        if(n==0 && m == 0) break;
        int i,j;
        for(i=1; i<=n; i++)
            for(j=1; j<=n; j++)
                edge[i][j] = INF;
        for(i=0; i<m; i++)
        {
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            edge[u][v] = edge[v][u] = w;
        }
        printf("System #%d\n",++ser);
        Dijkstra();
    }
    return 0;
}