[数据结构与算法]Educational Codeforces Round 124 (Rated for Div. 2) Nearest Excluded Points

#include<bits/stdc++.h>
// #define int long long
using namespace std;
const int N=200005;
map<pair<int,int>,int> mp,vis;
map<pair<int,int>,pair<int,int> > ans;
int n,x[N],y[N];
int dr[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        scanf("%d%d",&x[i],&y[i]);
        mp[{x[i],y[i]}]=1;
    }
    queue<pair<int,int>> q;
    for(int i=1;i<=n;i++){
        for(int j=0;j<4;j++){
            int xx=x[i]+dr[j][0],yy=y[i]+dr[j][1];
            if(mp.count({xx,yy})==0){
                ans[{x[i],y[i]}]={xx,yy};
                q.push({x[i],y[i]});
                vis[{x[i],y[i]}]=1;
                continue;
            }
        }
    }
    while(q.size()){
        auto tp=q.front();q.pop();
        int x=tp.first,y=tp.second;
        for(int j=0;j<4;j++){
            int xx=x+dr[j][0],yy=y+dr[j][1];
            if(mp.count({xx,yy})==1&&vis[{xx,yy}]==0){
                vis[{xx,yy}]=1;
                ans[{xx,yy}]=ans[{x,y}];
                q.push({xx,yy});
            }
        }
    }
    for(int i=1;i<=n;i++){
        cout<<ans[{x[i],y[i]}].first<<" "<<ans[{x[i],y[i]}].second<<endl;
    }
    
    
}