2609. 最长平衡子字符串

没什么难度，就是遍历然后计数

class Solution {
public:
    int findTheLongestBalancedSubstring(string s) {
        int ans = 0;
        int count0 = 0, count1 = 0;
        for(auto c:s){
            if(count1 == 0 && c == '0'){
                count0++;
            }else if(count1 != 0 && c == '0'){
                count0 = 1;
                count1 = 0;
            }else if(count0 != 0 && c == '1'){
                count1++;
                if(count0 >= count1) ans = max((count1 + count1), ans);
            }else{
                ans = 0;
            }
        }
        return ans;
    }
};