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

 1 class Solution
 2 {
 3     public:
 4         int minFlipsMonoIncr(string S)
 5         {
 6             vector<int> left2CountOne (S.size(),0);
 7             vector<int> right2CountZero (S.size(),0);
 8             
 9             for(int i = 0;i < S.size();i ++)
10             {
11                 if(S[i]=='1')
12                 {
13                     if(i==0)
14                         left2CountOne[i] = 1;
15                     else
16                         left2CountOne[i] = left2CountOne[i-1] + 1;
17                 }
18                 else if(S[i]=='0' && i!=0)
19                     left2CountOne[i] = left2CountOne[i-1];
20             }
21             
22             for(int i = S.size()-1;i >= 0 ;i --)
23             {
24                 if(S[i]=='0')
25                 {
26                     if(i==S.size()-1)
27                         right2CountZero[i] = 1;
28                     else
29                         right2CountZero[i] = right2CountZero[i+1] + 1;
30                 }
31                 else if(S[i]=='1' && i != S.size()-1)
32                     right2CountZero[i] = right2CountZero[i+1];
33             }
34             
35             int result = right2CountZero[0];
36             for(int i = 0;i < S.size()-1;i ++)
37             {
38                 if(left2CountOne[i]+right2CountZero[i+1] < result)
39                     result = left2CountOne[i]+right2CountZero[i+1];
40             }
41             if(result > left2CountOne[S.size()-1])
42                 result = left2CountOne[S.size()-1];
43         //    cout << left2CountOne[S.size()-1] << endl;
44             return result;
45         }
46 };