转 求中位数

 public double findMedianSortedArrays(int A[], int B[]) {
                // Start typing your Java solution below
                // DO NOT write main() function
                 
                int m = A.length, n = B.length;
                 
                //if m+n is even, then the median is the average of (m+n)/2 and (m+n)/2 - 1
                //if m+n is odd, then the median is (m+n)/2
         
                int mid = (m+n)/2;
                //look for mid in A
                //[start, end]: close region to try. inclusive.
                int start = 0, end = m-1, i = 0, j = 0;
                int median = 0;
                while (start <= end) {
                    i = (start+end)/2;
                    j = mid - i;
                    if (get(B, j-1) <= get(A, i) && get(A, i) <= get(B, j)) //index out of bound here.
                    {
                        median = get(A, i);
                        break;
                    }
                    else if (get(A, i)< get(B, j-1)) { //A[i] is smaller than the median
                        start = i + 1;
                        i = (start+end)/2;
                        j = mid - i;
                    }
                    else if (get(A, i) > get(B, j)) { //A[i] is bigger than the median
                        end = i - 1;
                        i = (start+end)/2;
                        j = mid - i;
                    }
                }
                 
                if (start <= end) //found the median
                {
                    if ((m+n) % 2 == 0) { //index out of bound here
                        int other = Math.max(get(A, i-1), get(B, j-1));
                        return (median + other) * 0.5;
                    }
                    else {
                        return (double)median;
                    }