暴力

#include <iostream>
#include <algorithm>

using namespace std;

#define M 26

int main() {
    string a;
    a = "abcdefghijklmnopqrstuvwxyz";
    const string stand = a;
    string b;
    cin >> b;
    int acc = 0;
    int len=b.size();
    int result = len + 1;
    int r = 0;
    int l = 0;
    int al=0;
    for (l = 0, r = 59; l < len && r < len;) {
        for (int m = l; m <= r; m++) {
            al=a.find(b[m]);
            if (al != -1) {
                acc++;
                a.erase(al, 1);
            }
        }
        if (acc == 26) {
            int temp=r-l+1;
            result = min(result, temp);
            l++;
        } else {
            r++;
        }
        a = stand;
        acc = 0;
    }
    cout << result;
    return 0;
}