Submission

Score: 100

User: peilin

Problemset: มุมขวาบน

Language: c

Time: 0.002 second

Submitted On: 2025-10-12 18:01:04

#include <stdio.h>
#include <math.h>

int main() {
    long long n;
    scanf("%lld", &n);

    if (n == 1) {
        printf("1\n");
        return 0;
    }

    long long k;
    long long k_base = (long long)ceil(sqrt((double)n));
    
    if (k_base % 2 == 0) {
        k = k_base + 1;
    } else {
        k = k_base;
	}
    if (k > 1) {
        long long corner_value = (k - 2) * (k - 2) + 3 * (k - 2) + 1;
        
        if (n <= corner_value) {
            k -= 2;
        }
    }

    long long top_right = k * k - (k - 1);
    
    printf("%lld\n", top_right);

    return 0;
}