Codeforces Round #549 (Div. 2) C Queen

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题解，题意都在代码里..

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
#define int long long 
const int maxn=1e5+5;

int s[maxn];
signed main(){
    /*  On each step you select such a non-root vertex that it does not respect its parent and none of its children respects it.

        ci=0, if the vertex i respects its parents, and ci=1, if the vertex i does not respect any of its parents.
    */
    
    int n;cin>>n;
    for(int i=1;i<=n;i++){
        int x,y;cin>>x>>y;
        if(x==-1){
            s[i]=1;//for root i;
            continue;
        }
        else{
            if(y==0){
                s[x]=1;//for skipped
                s[i]=1;//for vect i has child no condition
            }
        }
    }
    vector<int>ve;
    for(int i=1;i<=n;i++){
        if(!s[i])ve.push_back(i);
    }
    
    if(ve.empty())cout<<"-1"<<endl;
    else for(auto it:ve)cout<<it<<" ";
    return 0;
}