51nod 1127 最短的包含字符串

#include <iostream>
#include <cstdio>
#include <algorithm>
#define MAX 100001
using namespace std;

char s[MAX];
int m = MAX;
int main() {
    int head = 0,tail = 0,c = 0,num[26] = {0};
    scanf("%s",s);
    while(s[tail] || c == 26) {
        if(c < 26) {
            int d = s[tail ++] - ‘A‘;
            if(!num[d]) c ++;
            num[d] ++;
        }
        else {
            m = min(m,tail - head);
            int d = s[head ++] - ‘A‘;
            if(num[d] == 1) c --;
            num[d] --;
        }
    }
    if(m != MAX)printf("%d\n",m);
    else printf("No Solution\n");
}