1491. 원재의 벽 꾸미기(D3)

#include <stdio.h>
#include <math.h>
unsigned long long min = 2e9;
unsigned long long cal(long long a, long long b, long long n, long long r, long long c) {
    long long temp;
    if(r>c)
        temp=a*(r - c) + b*(n - (r*c));
    else
        temp= a*(c - r) + b*(n - (r*c));
 
    return temp;
}
int main(void)
{    
    int test_case;
    scanf("%d\n", &test_case);
    for (int z = 1; z<= test_case; z++) {
        min = 2e9;
        int n, a, b;
        scanf("%d%d%d", &n,&a,&b);
        for (int i = 1; i <=sqrt(n); i++) {
            for (int j = sqrt(n) /2; j <= n; j++) {
                if (i*j <= n) {
                    unsigned long long temp = cal(a, b, n, i, j);
 
                    if (temp < 0) {
                        continue;
                    }
                    if (temp < min) {
                        min = temp;
                    }
                }
                else {
                    break;
                }
            }
        }
        printf("#%d %llu\n", z, min);
    }
    return 0;
}