Submission #306029

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Source Code Expand

#include <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define each(it,n) for(__typeof((n).begin()) it=(n).begin();it!=(n).end();++it)

using namespace std;

typedef long long ll;

vector<pair<ll, ll> > points;
map<pair<ll, ll>, int> s;
int n;

void doit() {
    rep(i, n) {
        for (int j = i + 1; j < n; j++) {
            pair<ll, ll> p1 = points[i], p2 = points[j];
            pair<ll, ll> vec(p1.first - p2.first, p1.second - p2.second);
            
            pair<ll, ll> p3, p4;
            p3 = pair<ll, ll>(p1.first + vec.second, p1.second - vec.first);
            p4 = pair<ll, ll>(p2.first + vec.second, p2.second - vec.first);

            if (s.find(p3) != s.end() && s.find(p4) != s.end()) {
                cout << 4 << endl;
                vector<int> ans = {i + 1, j + 1, s[p3] + 1, s[p4] + 1};
                sort(ans.begin(), ans.end());
                rep(i, 4) {
                    cout << ans[i] << endl;
                }
                return;
            }

            p3 = pair<ll, ll>(p1.first - vec.second, p1.second + vec.first);
            p4 = pair<ll, ll>(p2.first - vec.second, p2.second + vec.first);

            if (s.find(p3) != s.end() && s.find(p4) != s.end()) {
cout << 4 << endl;
                vector<int> ans = {i + 1, j + 1, s[p3] + 1, s[p4] + 1};
                sort(ans.begin(), ans.end());
                rep(i, 4) {
                    cout << ans[i] << endl;
                }
                return;
            }
        }
    }
    cout << 0 << endl;
}

int main() {
    cin >> n;

    points = vector<pair<ll, ll> >(n);

    rep(i, n) {
        cin >> points[i].first >> points[i].second;
        s[points[i]] = i;
    }

    doit();
    
    return 0;
}

Submission Info

Judge Result