CF-201A to find the law

Test instructions

Give a number n, requires the minimum length of the square matrix X, to ensure that the x*x policy has n lattice 1, the remaining lattice are 0, and to ensure that the matrix up and down, around the symmetrical, output x.

Ideas:

No idea, draw a few more rules, found that x must be odd, and N to meet a certain relationship. Note that 3 is required for a special sentence.

Code:

#include <bits/stdc++.h>
using namespace std;

int main () {
    int n, i;
    scanf ("%d", &n);
    for (i = 1; (I * i + 1)/2 < n; i + = 2);
    printf ("%d\n", n = = 3? 5:i);
    return 0;
}