Leetcode-930 Binary Subarrays With Sum(和相同的二元子数组)

 1 class Solution
 2 {
 3     public:
 4         int numSubarraysWithSum(vector<int>& A, int S)
 5         {
 6             if(S==0)
 7             {
 8                 int result = 0;
 9                 int count = 0;
10                 for(int i = 0; i < A.size(); i ++)
11                 {
12                     if(A[i]==0)
13                         count ++;
14                     else
15                     {
16                         result += (count+1)*count/2;
17                         count = 0;
18                     }
19                 }
20                 if(count)
21                 {
22                     result += (count+1)*count/2;
23                     count = 0;
24                 }
25                 return result;
26             }
27             int totalResult = 0;
28 
29             int left = 0,right = 0;
30             int oneSum = 0;
31             int result = 0;
32             for(; right < A.size(); right ++)
33             {
34                 if(oneSum < S)
35                 {
36                     if(A[right]==1)
37                         oneSum ++;
38                 }
39                 if(oneSum == S)
40                 {
41                     int leftResult = 1,rightResult = 1;
42                     while(right != A.size()-1 && A[right+1]==0)
43                     {
44                         right ++;
45                         rightResult ++;
46                     }
47                     if(A[left]==1)
48                         ;
49                     else
50                     {
51                         while(left < right && A[left+1]==0)
52                         {
53                             left ++;
54                             leftResult ++;
55                         }
56                         left ++;
57                         leftResult ++;
58                     }
59                     result += leftResult*rightResult;
60                     left ++;
61                     oneSum --;
62                 }
63             }
64             return result;
65         }
66 };