Jiudu question 1448: Legal or Not, 1448 legal

Jiudu question 1448: Legal or Not, 1448 legal

This article uses topological sorting to determine whether a ring exists. If the number of output nodes is less than N, a ring is formed, which is almost the same as the previous Code 1449.

Question link http://ac.jobdu.com/problem.php? Pid = 1, 1448

Reprinted please indicate this article address http://blog.csdn.net/yangnanhai93/article/details/41226369

#include <iostream>#include <memory.h>#include <queue>using namespace std;int A[100],MapCount[100][100];bool TopoSort(int n){    queue<int> qu;    for(int i=0;i<n;i++)        if(A[i]==0)            qu.push(i);    int count=0;    while(!qu.empty())    {        int front=qu.front();        qu.pop();        count++;        for (int i=0;i<n;i++)        {            if(MapCount[front][i])            {                A[i]--;                if(A[i]==0)                    qu.push(i);            }        }    }    if(count==n)        return true;    else        return false;}int main(){    //freopen("data.in","r",stdin);    int m,n,x,y;    while(cin>>m>>n&&m)    {        memset(A,0,sizeof(A));        memset(MapCount,0,sizeof(MapCount));        for(int i=0;i<n;i++)        {            cin>>x>>y;            MapCount[x][y]=1;        }        for(int i=0;i<m;i++)            for(int j=0;j<m;j++)                if(MapCount[i][j]!=0)                    A[j]++;         if(TopoSort(m))            cout<<"YES"<<endl;        else            cout<<"NO"<<endl;    }    return 0;}/**************************************************************    Problem: 1448    User: vincent_ynh    Language: C++    Result: Accepted    Time:10 ms    Memory:1560 kb****************************************************************/