coderforce 540A Combination Lock

题意：给你两串数字，每次可以改变一位，实现+1，-1操作，且9+1=0&&0-1=9。求最少多少步，才能使s1变到s2.

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
const int maxm=1e4+10;
char s1[maxm];
char s2[maxm];
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        scanf("%s%s",s1,s2);
        int cnt=0;
        for(int i=0;i<n;i++)
        {
            int x=s1[i]-'0';
            int y=s2[i]-'0';
            int step=min((min(x,y)+10-max(x,y)),max(x,y)-min(x,y));
            cnt+=step;
        }
        printf("%d\n",cnt);
    }
    return 0;
}