24| 字符串

代码实现

const int N = 30;
string s;
int a[N];
int main()
{
	cin >> s;
	int n = s.size();
	int l = 0, r = 0, kind = 0, ret = n;
	while(r < n)
	{
		// 进窗口
		if (islower(s[r]))
		{
			a[s[r] - 'a'] ++;
			if (a[s[r] - 'a'] == 1) kind++;
		 } 
		 while(kind == 26)
		 {
		 	// 更新结果 
		 	ret = min(ret, r - l + 1);
		 	
		 	// 出窗口
			 if (islower(s[l])) 
			 {
			 	a[s[l] - 'a'] --;
			 	if (a[s[l] - 'a'] == 0) kind--;
			 }
			 l++;
		 }
		 r++;
	}
	cout << ret << endl;
 }