sicily 1155. Can I Post the lette

#include <iostream>        //求顶点1到n是否可达
#include<stdio.h>
#include<cstring>
using namespace std;
int n,m,edge[200][200];
int seq[50000],vis[50000];
int main()
{        
    while(scanf("%d",&n),n)
    {        
        memset(edge,0,sizeof(edge));    
        memset(vis,0,sizeof(vis));
        int s,t;
        scanf("%d",&m);
        while(m--)    
        {
            scanf("%d%d",&s,&t);
            edge[s][t]=1;
        }
        seq[0]=0;
        int fro=0,rear=1,suc=0;
        while(fro<rear)
        {
            int v=seq[fro++];
            for(int i=0;i<n;++i)
            {
                if(vis[i]==0&&edge[v][i]==1)
                {
                    vis[i]=1;
                    seq[rear++]=i;
                    if(i==n-1)
                    {
                        suc=1;
                        break;
                    }
                }
            }
            if(suc==1)
                break;
        }
        if(suc==1)
            printf("I can post the letter\n");
        else
            printf("I can't post the letter\n");
    }
    return 0;
}