Codeforces Round #239 (Div. 2), problem: (B) Garland solution

Codeforces Round #239 (Div. 2), problem: (B) Garland: http://codeforces.com/contest/408/problem/B

Codeforces Round #239 (Div. 2), problem: (B) Garland editorial: http://codeforces.com/blog/entry/11333

Codeforces Round #239 (Div. 2), problem: (B) Garland solution: http://ideone.com/2Ls7nn

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int main() {
    int a[50], b[50], cnt, flag;
    char s1[1005], s2[1005];
    memset(a, 0, sizeof(a));
    memset(b, 0, sizeof(b));
    cnt=flag=0;
    scanf("%s%s", s1, s2);
    for(int i=0; i<strlen(s1); i++) a[s1[i]-97]++;
    for(int i=0; i<strlen(s2); i++) b[s2[i]-97]++;
    for(int i=0; i<50; i++) {
        cnt+=min(a[i], b[i]);
        if(a[i]==0 && b[i]>0) {
            flag=1;
            break;
        }
    }
    if(flag) printf("-1");
    else printf("%d", cnt);
    return 0;
}