Submission #1781513

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define mod 1000000007
#define fi first
#define sc second
#define rep(i,x) for(int i=0;i<x;i++)
#define repn(i,x) for(int i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())
int n;
int x[1005],y[1005];
map<P,int>M;
int main(){
	cin>>n;
	repn(i,n){
		cin>>x[i]>>y[i];
		M[mp(x[i],y[i])] = i;
	}
	repn(i,n) repn(j,n){
		if(i==j) continue;
		int a = x[j]-x[i],b = y[j]-y[i];
		int X = x[j]-b,Y = y[j]+a;
		int XX = X-a,YY = Y-b;
		if(M.find(mp(X,Y)) != M.end() && M.find(mp(XX,YY)) != M.end()){
			cout<<4<<endl;
			vector<int>vi; vi.pb(i); vi.pb(j); vi.pb(M[mp(X,Y)]); vi.pb(M[mp(XX,YY)]);
			SORT(vi);
			rep(k,4)cout<<vi[k]<<endl;
			return 0;
		}
	}
	puts("0");
}

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