AcWing——3624. 三值字符串

双指针解法

#include<iostream>
#include<unordered_map>
using namespace std;
int main() {
	int n; cin >> n;
	while(n--){
	    unordered_map<char, int> tree;
	    string s; cin >> s;
	    int ans = 0x7fffffff; 
	    for(int i = 0, j = 0; j < (int)s.size(); j++){
	        tree[s[j]]++;
	        while(tree[s[i]] > 1) tree[s[i++]]--;
	        if(tree['1'] && tree['2'] && tree['3'])
	          ans = min(ans, j-i+1);
	    }
	    if(ans == 0x7fffffff)  cout << 0 << '\n';
	    else cout << ans << '\n';
	}
	return 0;
}