拓扑排序 hihoCcoder1174 拓扑排序·一

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<queue>
#include<algorithm>

using namespace std;
typedef long long LL;

const int mod=1e9+7;
const int MX=100000+5;
const int INF=0x3f3f3f3f;

int vis[MX];
vector<int>G[MX];

bool DFS(int u){
if(vis[u]==-1) return true;

vis[u]=1;
for(int i=0;i<G[u].size();i++){
int v=G[u][i];

if(vis[v]==1||!DFS(v)) return false;
}
vis[u]=-1;
return true;
}

int main(){
int T,n,m;
scanf("%d",&T);

while(T--){
scanf("%d%d",&n,&m);

memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++) G[i].clear();

for(int i=1;i<=m;i++){
int u,v;
scanf("%d%d",&u,&v);
G[u].push_back(v);
}

bool ans=true;
for(int i=1;i<=n;i++){
ans&=DFS(i);
if(!ans)    break;
}

printf("%s\n",ans?"Correct":"Wrong");
}
return 0;
}

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<queue>
#include<algorithm>

using namespace std;
typedef long long LL;

const int mod=1e9+7;
const int MX=100000+5;
const int INF=0x3f3f3f3f;

int vis[MX],A[MX];
vector<int>G[MX];

int main(){
int T,n,m;
scanf("%d",&T);

while(T--){
scanf("%d%d",&n,&m);

memset(A,0,sizeof(A));
memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++) G[i].clear();

for(int i=1;i<=m;i++){
int u,v;
scanf("%d%d",&u,&v);
G[u].push_back(v);
A[v]++;
}

int cnt=0;
queue<int>work;

for(int i=1;i<=n;i++){
if(A[i]==0) work.push(i);
}
while(!work.empty()){
int fp=work.front();
work.pop();cnt++;

for(int i=0;i<G[fp].size();i++){
int v=G[fp][i];
A[v]--;
if(!A[v]) work.push(v);
}
}

printf("%s\n",cnt==n?"Correct":"Wrong");
}
return 0;
}