P1347 排序

P1347 排序
floyed判环，水过。

#include<iostream>
#include<cstdio>
#include<queue>
#include<algorithm>
#include<cmath>
#include<ctime>
#include<cstring>
#define inf 2147483647
#define For(i,a,b) for(register int i=a;i<=b;i++)
#define p(a) putchar(a)
#define g() getchar()
//by war
//2017.10.25
using namespace std;
int n,m,x;
char a[4];
bool f[1000][1000];
char ans[1000];
void in(int &x)
{
    int y=1;
    char c=g();x=0;
    while(c<'0'||c>'9')
    {
    if(c=='-')
    y=-1;
    c=g();
    }
    while(c<='9'&&c>='0')x=x*10+c-'0',c=g();
    x*=y;
}
void o(int x)
{
    if(x<0)
    {
        p('-');
        x=-x;
    }
    if(x>9)o(x/10);
    p(x%10+'0');
}

int floyed()
{
    int sum=0;
    For(k,'A','A'+n-1)
      For(i,'A','A'+n-1)
        For(j,'A','A'+n-1)
          if(f[i][k]&&f[k][j])
            f[i][j]=true;
    For(i,'A',n+'A'-1)
    if(f[i][i])
    return 0;
    bool flag=false;
    For(k,1,n)
    {
        sum=0;
        flag=false;
        For(i,'A','A'+n-1)
         {
           sum=0;
           For(j,'A','A'+n-1)
            if(f[i][j])
            sum++;
            
              if(sum==n-k)
              {
              ans[k]=(char)i;
              flag=true;
              break;    
              }
        }
        if(!flag)
        return 2;
    }
    return 1;
}

int main()
{
    in(n),in(m);
    For(i,1,m)
    {
        cin>>a;
        f[a[0]][a[2]]=true;
        x=floyed();
        if(x==0)
        {
        printf("Inconsistency found after %d relations.",i);
        exit(0);    
        }
        else
        if(x==1)
        {
        printf("Sorted sequence determined after %d relations: ",i);
        For(j,1,n)
        printf("%c",ans[j]);
        printf(".");
        exit(0);    
        }
    }
    printf("Sorted sequence cannot be determined.");
     return 0;
}