topsort()

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1174 : 拓扑排序·一

题目链接

#include<iostream>#include<cstdio>#include<cstring>#include<vector>#include<queue>using namespace std;const int N = 100005;int indx[N];vector<int>G[N];int topsort(int n){    int ans=0;    queue<int>q;    for(int i=1;i<=n;i++){        if(indx[i]==0){            q.push(i);            ans++;        }    }    while(!q.empty()){        int fp=q.front();        q.pop();        for(int i=0;i<G[fp].size();i++){            int v = G[fp][i];            indx[v]--;            if(indx[v]==0){                q.push(v);                ans++;            }        }    }    return ans;}int main(){    int T;    scanf("%d",&T);    while(T--){        int n,m;        memset(indx,0,sizeof(indx));        scanf("%d%d",&n,&m);        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);            indx[v]++;        }        int ans=0;        ans=topsort(n);        if(ans==n)            printf("Correct\n");        else            printf("Wrong\n");    }    return 0;}

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