Labeling Balls POJ

优先队列 + 反向拓扑

//#include<bits/stdc++.h>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<cstring>
using namespace std;
const int maxn = 1e5 + 7;
int n, m;
vector<int>G[maxn];
int inDeg[maxn];
int dp[maxn];
int cnt;
int sum ,ans ;
int mp[1000][1000];
bool topsort()
{
    //queue<int>q;
    priority_queue<int>q;
    //queue<int>q;
    cnt = 0;
    sum = 0;
    while(!q.empty())q.pop();
    for(int i = 1; i <= n ; i++) if(!inDeg[i]) q.push(i);
    while(!q.empty())
    {
        int now = q.top();
        q.pop();
      //  cout << now << endl;
      sum ++;
        dp[now] = n--;
      //  cout << dp[now] << endl;
        for(int i = 0; i < G[now].size(); i++)
        {
            int to = G[now][i];
            inDeg[to]--;
            if(!inDeg[to]) q.push(to);
        //    dp[to] = max(dp[to],dp[now] + G[now][i].second);
        }

    }
if(sum == ans)return 1;
else return 0;
}

int main()
{
    int t;
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
  //  cin >> t;
     cin >> t;
     while(t--){
     
        cin >> n >> m;
        ans = n;
        memset(inDeg,0,sizeof inDeg);
        memset(dp,0,sizeof dp);
        for(int i = 1; i <= n ; i++) G[i].clear();
        while(m--)
        {
            int u, v, w;
            cin >> u >> v ;
            
            //if(mp[u][v] == 0)
            G[v].push_back(u);
            
            //G[v].push_back(make_pair((u,w)));
            inDeg[u] ++;
        }
        if(topsort())
        //int maxx = 0;
        for(int i  = 1; i <= ans ; i++)
        printf("%d%c",dp[i]," 
"[i == ans]);
        else 
        puts("-1");
    }
    return 0;
}