Closest points

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define pb push_back
#define VI vector<int>
#define AR(x) array<ll, x>
#define MX vector<VI >
#define all(x) x.begin(), x.end()
#define IOS cin.tie(0)->sync_with_stdio(0)

using namespace std;

int main(){

    IOS;

    int n;
    cin >> n;

    vector<AR(2) > p(n);
    for(auto &[x, y] : p) cin >> x >> y;

    sort(all(p));

    auto swp = [](const AR(2) &a) -> AR(2) { return {a[1], a[0]}; };

    auto dist = [](const AR(2) &a, const AR(2) &b){
        return ((ll)a[0]-b[0])*((ll)a[0]-b[0])+((ll)a[1]-b[1])*((ll)a[1]-b[1]);
    };

    const int inf = 1e9+2;
    ll ans = 8e18;
    multiset<AR(2)> s;
    int j = 0;
    for(auto c : p){
        while(j < n && ((ll)p[j][0]-c[0])*((ll)p[j][0]-c[0]) >= ans){
            s.erase(s.find(swp(p[j++])));
        }
        auto l = s.upper_bound({c[1]-ans, -inf});
        auto r = s.upper_bound({c[1]+ans, inf});
        for(auto it = l; it!=r; it++){
            ans = min(ans, dist(*it, swp(c)));
        }
        s.insert(swp(c));
    }

    cout << ans << '\n';

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED