Case of the Zeros and Ones 分类： CF 2015-07-24 11:05 15人阅读 评论(0) 收藏

A. Case of the Zeros and Ones

time limit per test
1 second

memory limit per test
256 megabytes

input
standard input

output
standard output

Andrewid the Android is a galaxy-famous detective. In his free time he likes to think about strings containing zeros and ones.

Once he thought about a string of length n consisting of zeroes and ones. Consider the following operation: we choose any twoadjacent positions in the string, and if one them contains
0, and the other contains 1, then we are allowed to remove these two digits from the string, obtaining a string of lengthn - 2 as a result.

Now Andreid thinks about what is the minimum length of the string that can remain after applying the described operation several times (possibly, zero)? Help him to calculate this number.

Input
First line of the input contains a single integer n (1 ≤ n ≤ 2·105), the length of the string that Andreid has.

The second line contains the string of length n consisting only from zeros and ones.

Output
Output the minimum length of the string that may remain after applying the described operations several times.

Sample test(s)

Input

4
1100

Output

0

Input

5
01010

Output

1

Input

8
11101111

Output

6
CF的一道水题
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <stack>
#include <algorithm>

using namespace std;

const int MAX = 200200;

char str[MAX];

int main()
{
int n;
scanf("%d",&n);
scanf("%s",str);
int a=0,b=0;
for(int i=0;i<n;i++)
{
if(str[i]=='0')
{
a++;
}
else
{
b++;
}
}
int sum=abs(a-b);
printf("%d\n",sum);
return 0;

}