PKU 1094 关系矩阵实现的拓朴排序

PKU 1094 关系矩阵实现的拓朴排序

题目分的三种情况 不能有环出现
判断环的时候在处理输入的时候判断 另外还在处理完后有一个三重循环的判断

这个代码是参考过别人的 最近没怎么做 手很生···

#include <iostream>
using namespace std;

int sorted[27];
int map[27][27];
char str[200][4];
int main()
{
 int n,m;

 int t;
 int i,j,k;
L2:
 while(scanf("%d%d",&n,&m)==2 && n &&m)
 {

  for(t=1;t<=m;t++)
   scanf("%s",str[t]);

  memset(map,0,sizeof(map));

  for(t=1;t<=m;t++)
  {   
   i=str[t][0]-'A'+ 1;
   j = str[t][2]-'A'+ 1;
   switch(str[t][1])
   {
    case '>':
     if(map[i][j] == -1 || map[j][i] == 1)
      goto RESTRIC;
     map[i][j] = 1;
     map[j][i] = -1;
     break;
    case '<':
     if(map[i][j] == 1 || map[j][i] == -1)
      goto RESTRIC;
     map[i][j] = -1;
     map[j][i] = 1;
     break;
   }
   
   for(k=1;k<=n;k++)
    for(i=1;i<=n;i++)
     for(j=1;j<=n;j++)
     {
      if(map[i][k] && map[k][j] && k!=i && i!=j )
      {
       if(!map[i][j])
       {
        if(map[i][k] == map[k][j])
        {
         map[i][j] = map[i][k];
         map[j][i] = -map[i][k];
        }
       }
       else
       {
        if(map[i][k] == map[k][j])
        {
         if(map[i][k] != map[i][j])
          goto RESTRIC;
        }
       }
      }
     }
 
   for(i=1;i<=n;i++)
   {
    int p = 1;
    for(j=1;j<=n;j++)
    {
     if(i!=j)
     {
      if(map[i][j] == 0)
       goto L;
      if(map[i][j] == 1)
       p++;
     }
    }
    sorted[p] = i;
   }
   
   printf("Sorted sequence determined after %d relations: ",t);
   for(i=1;i<=n;i++)
    putchar(sorted[i]+'A'-1);
   printf(".\n");
   goto L2;
L:
 ;    
  }
  
  printf("Sorted sequence cannot be determined.\n");
  
  continue;
RESTRIC:
  printf("Inconsistency found after %d relations.\n",t);
   
 }
 return 0;
}