2609. Find the Longest Balanced Substring of a Binary String

class Solution {
public:
    int findTheLongestBalancedSubstring(string s) {
        int cntZeros=0, ans=0, max=0;

        int a = 0, b = 0;
        for(int i=0; i<s.length(); i++)
        {
            if(s[i]=='0')
            {
                cntZeros++;
                a=1;
            }
            else if(s[i]=='1' && cntZeros>0)
            {
                max++;
                cntZeros--;
                b=1;
            }

            if(max > ans)
            {
                ans = max;
            }

            if(a==1)
            {
                max=0;
                a=0;
            }

            if(b==1 && s[i]=='0')
            {
                cntZeros=1;
                b=0;
            }

        }        
        return 2*ans;
    }
};