Leetcode-926 Flip String to Monotone Increasing(将字符串翻转到单调递增)

class Solution
{
    public:
        int minFlipsMonoIncr(string S)
        {
            vector<int> left2CountOne (S.size(),0);
            vector<int> right2CountZero (S.size(),0);
            
            for(int i = 0;i < S.size();i ++)
            {
                if(S[i]=='1')
                {
                    if(i==0)
                        left2CountOne[i] = 1;
                    else
                        left2CountOne[i] = left2CountOne[i-1] + 1;
                }
                else if(S[i]=='0' && i!=0)
                    left2CountOne[i] = left2CountOne[i-1];
            }
            
            for(int i = S.size()-1;i >= 0 ;i --)
            {
                if(S[i]=='0')
                {
                    if(i==S.size()-1)
                        right2CountZero[i] = 1;
                    else
                        right2CountZero[i] = right2CountZero[i+1] + 1;
                }
                else if(S[i]=='1' && i != S.size()-1)
                    right2CountZero[i] = right2CountZero[i+1];
            }
            
            int result = right2CountZero[0];
            for(int i = 0;i < S.size()-1;i ++)
            {
                if(left2CountOne[i]+right2CountZero[i+1] < result)
                    result = left2CountOne[i]+right2CountZero[i+1];
            }
            if(result > left2CountOne[S.size()-1])
                result = left2CountOne[S.size()-1];
        //    cout << left2CountOne[S.size()-1] << endl;
            return result;
        }
};