POJ1844Sum

易水人去，明月如霜。

Description

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.

Input

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

Output

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

Sample Input

12

Sample Output

7

Hint

The sum 12 can be obtained from at least 7 terms in the following way: 12 = -1+2+3+4+5+6-7.

太简单

#include <cstdio>#include <cstring>#include <cmath>using namespace std;int main(){int n;scanf("%d",&n);for(int i=1;i<=n;i++){    if((i*(i+1))/2<n) continue;    int d=i*(i+1)/2;    if((d-n)%2==0) {        printf("%d",i);        break;    }} return 0;}