leetcode find median sorted arrays python

# @link http://www.cnblogs.com/zuoyuan/p/3759682.html

class Solution(object):
    def findMedianSortedArrays(self, nums1, nums2):
        """
        :type nums1: List[int]
        :type nums2: List[int]
        :rtype: float
        """
        len1 = len( nums1 )
        len2 = len( nums2 )
        if( len1 + len2 ) % 2 == 1:
            return self.getKth(nums1,nums2,(len1+len2)/2 + 1)
        else:
            return ( self.getKth(nums1,nums2,(len1+len2)/2) + self.getKth(nums1,nums2,(len1+len2)/2+1) ) * 0.5

    def getKth(self,nums1,nums2,k):
        len1 = len(nums1)
        len2 = len(nums2)
        if len1 > len2:
            return self.getKth(nums2,nums1,k)
        if len1 == 0:
            return nums2[k-1]
        if k == 1:
            return min( nums1[0],nums2[0])
        pa = min(k/2,len1)
        pb = k - pa
        if nums1[pa-1] < nums2[pb-1]:
            return self.getKth(nums1[pa:],nums2,pb)
        else:
            return self.getKth(nums1,nums2[pb:],pa)