4. Median of Two Sorted Arrays

 1 static int wing=[]()
 2 {
 3     std::ios::sync_with_stdio(false);
 4     cin.tie(NULL);
 5     return 0;
 6 }();
 7 
 8 class Solution 
 9 {
10 public:
11     double findMedianSortedArrays(vector<int>& A, vector<int>& B) 
12     {
13         int m=A.size(),n=B.size();
14         if(m>n)
15         {
16             swap(A,B);
17             swap(m,n);
18         }
19         if(n==0)
20             return -1.0;
21         int imin=0,imax=m,half_len=(m+n+1)/2;
22         while(imin<=imax)
23         {
24             int i=(imin+imax)/2;
25             int j=half_len-i;
26             if(i<m&&B[j-1]>A[i])
27                 imin=i+1;
28             else if(i>0&&A[i-1]>B[j])
29                 imax=i-1;
30             else
31             {
32                 int max_of_left=0;
33                 if(i==0)
34                     max_of_left=B[j-1];
35                 else if(j==0)
36                     max_of_left=A[i-1];
37                 else
38                     max_of_left=max(A[i-1],B[j-1]);
39                 
40                 if((m+n)%2==1)
41                     return max_of_left;
42                 
43                 int min_of_right=0;
44                 if(i==m)
45                     min_of_right=B[j];
46                 else if(j==n)
47                     min_of_right=A[i];
48                 else
49                     min_of_right=min(A[i],B[j]);
50                 return (max_of_left+min_of_right)/2.0;
51             }
52         }
53     }
54 };