[LeetCode题解004]Median of Two Sorted Arrays

http://leetcode.com/onlinejudge#question_4

There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).

===分析===

这个问题的难点在于编程，界限不好确定。把这个问题改成求第k大的数之后就好办多了，抄袭了人家的源码..

http://blog.csdn.net/boyhou/article/details/9209149

===源码===

double findKth(int a[], int m, int b[], int n, int k)  {      //always assume that m is equal or smaller than n       if (m > n)          return findKth(b, n, a, m, k);      if (m == 0)          return b[k - 1];      if (k == 1)          return min(a[0], b[0]);      //divide k into two parts       int pa = min(k / 2, m), pb = k - pa;      if (a[pa - 1] < b[pb - 1])          return findKth(a + pa, m - pa, b, n, k - pa);      else if (a[pa - 1] > b[pb - 1])          return findKth(a, m, b + pb, n - pb, k - pb);      else          return a[pa - 1];  }    class Solution  {  public:      double findMedianSortedArrays(int A[], int m, int B[], int n)      {          int total = m + n;          if (total & 0x1)              return findKth(A, m, B, n, total / 2 + 1);          else              return (findKth(A, m, B, n, total / 2)                      + findKth(A, m, B, n, total / 2 + 1)) / 2;      }  };