Closest points

#include <bits/stdc++.h>

using namespace std;

//Definitions for quicker writing
#define REP(i,a,b) for (int i = a; i < b; i++)
#define clz __builtin_clz
#define ctz __builtin_ctz
#define popct __builtin_popcount
#define PB push_back
#define MP make_pair
#define F first
#define S second
#define X real()
#define Y imag()

//Typedefs for quicker writing
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef pair<int,int> pi;
typedef pair<long long, long long> pl;
typedef complex<long long> po;

//Max values
const long long lmx = LLONG_MAX;
const int imx = INT_MAX;

double cross(po v, po w){
    return v.X * w.Y - v.Y * w.X;
}

ll euclidean(po v, po w){
    ll x1,x2,y1,y2;
    x1 = v.X;
    x2 = w.X;
    y1 = v.Y;
    y2 = w.Y;
    ll sum;
    sum = (x2-x1)*(x2-x1)+(y2-y1)*(y2-y1);
    return sum;
}

bool comp(const po &a, const po &b) {
    return (a.X == b.X) ? (a.Y < b.Y) : (a.X < b.X);
}

int main() {
	//IO optimization
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	//Input definition
	ll n;

	//Read In
	cin >> n;

    po points[n];
    ll a,b;
    REP(i,0,n){
        cin >> a >> b;
        points[i] = {a,b};
    }

	//Main part
    sort(points,points+n, comp);
    ll x,y;
    ll d = euclidean(points[0],points[1]);
    REP(i,1,n){
        x = points[i].X;
        y = points[i].Y;
        for(int j = i-1; j >= 0; j--){
            if(points[j].X >= x-d){ 
                if(!(points[j].Y <= y+d && points[j].Y >= y-d)) continue;
                if(euclidean(points[j],points[i]) < d) d = euclidean(points[i],points[j]);
            }
            else{
                break;
            }
        }
    }
	

	//Write out
	cout << d << "\n";
		
	//Return
	return 0;

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: TIME LIMIT EXCEEDED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: TIME LIMIT EXCEEDED

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: TIME LIMIT EXCEEDED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED