Submission #64096937

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Source Code Expand

#include<bits/stdc++.h>
#define int long long
#define mod 1000000007LL
//#define endl '\n'
#define pii pair<int,int>
#define Mikari_My_Wife ios::sync_with_stdio(0),cin.tie(0);
#define all(x) x.begin(),x.end()
using namespace std;
int n;
vector<int>v[500];
map<pii,int>vis;
int dep[505];
void dfs_pre(int now,int pre,int now_deep){
    dep[now]=now_deep;
    for(auto nxt:v[now]){
        if(nxt==pre)continue;
        dfs_pre(nxt,now,now_deep+1);
    }
}
void solve(){
    cin>>n;
    for(int i=0;i<n-1;i++){
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
        vis[{x,y}]=1;
        vis[{y,x}]=1;
    }
    dfs_pre(1,1,0);
    set<pii>a;
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
            if(i==j||vis[{i,j}]||vis[{j,i}])continue;
            if((dep[i]+dep[j])%2==1){
                a.insert({i,j});
                a.insert({j,i});
            }
        }
    }
    // for(auto [aa,bb]:a){
    //     cout<<aa<<"~"<<bb<<endl;
    // }
    if(a.size()/2%2==0){
        cout<<"Second"<<endl;
        int x,y;
        while(cin>>x>>y){
            if(x==-1&&y==-1)return ;
            a.erase(a.find({x,y}));
            a.erase(a.find({y,x}));
            auto ow=*a.begin();
            a.erase(a.begin());
            cout<<ow.first<<" "<<ow.second<<endl;
            a.erase(a.find({ow.second,ow.first}));
        }
    }else {
        cout<<"First"<<endl;
        auto ow=*a.begin();
        a.erase(a.begin());
        cout<<ow.first<<" "<<ow.second<<endl;
        a.erase(a.find({ow.second,ow.first}));
        int x,y;
        while(cin>>x>>y){
            if(x==-1&&y==-1)return ;
            a.erase(a.find({x,y}));
            a.erase(a.find({y,x}));
            auto owo=*a.begin();
            a.erase(a.begin());
            cout<<owo.first<<" "<<owo.second<<endl;
            a.erase(a.find({owo.second,owo.first}));
        }
        
    }
}
signed main(){
    //注意多筆測資輸入！！！
    //Mikari_My_Wife
    int t=1;
    //cin>>t;
    while(t--){solve();}
}

Submission Info

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