Submission

Score: 100

User: Kidmaiok

Problemset: มุมขวาบน

Language: cpp

Time: 0.002 second

Submitted On: 2026-10-12 03:33:21

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define space << ' '
#define nl << endl

long long topright(long long n) {
    return 4 * n * n + 2 * n + 1;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int x;
    cin >> x;
    int n = 0,right = 0,previous = 1;
    while(right < x){
        previous = right;
        right = topright(n);
        n++;
    }
    if(right - x == 2){
        cout << "Cannot find top-right corner.";
    }else if(right - x == 1){
        cout << x;
    }else if(right == x){
        cout << right;
    }else {
        cout << previous;
    }
}