Sum

Consider the natural numbers from 1 to N. By associating to each number a sign (+ or -) and calculating the value of this expression we obtain a sum S. The problem is to determine for a given sum S the minimum number N for which we can obtain S by associating signs for all numbers between 1 to N. 

For a given S, find out the minimum value N in order to obtain S according to the conditions of the problem. 

The only line contains in the first line a positive integer S (0< S <= 100000) which represents the sum to be obtained.

The output will contain the minimum number N for which the sum S can be obtained.

12

7

#include <stdio.h>

int main()
{
    int s, sum, i;
    while(scanf("%d", &s) == 1){
        sum = i = 0;
        while(sum < s || (sum - s) & 1)
            sum += ++i;
        printf("%d\n", i);
    }
    return 0;
}