51Nod 1127 最短的包含字符串 滑窗算法

#include <bits/stdc++.h>
#define DBG(x) cerr << #x << " = " << x << endl

typedef long long LL;
using namespace std;

int main(int argc, char **argv) {
    string str;
    while(cin >> str) {
        unordered_map<char, int> vis;
        int ans = INT_MAX;
        int l = 0, r = 0;
        ++vis[str[r]];
        int num = 1;
        while(l <= r && r < str.size()) {
            if(num == 26) {
                ans = min(ans, r - l + 1);
                if(--vis[str[l++]] == 0) --num;
            } else {
                if(vis[str[++r]]++ == 0) ++num;
            }
        }
        if(ans == INT_MAX) cout << "No Solution" << endl;
        else cout << ans << endl;
    }
    return 0;
}

/**
BVCABCDEFFGHIJKLMMNOPQRSTUVWXZYZZ

28
*/