Leetcode-4. 寻找两个有序数组的中位数

######## 4. 寻找两个有序数组的中位数

class Solution(object):
    def findMedianSortedArrays(self, nums1, nums2):
        n1 = len(nums1)
        n2 = len(nums2)
        if n1 > n2:
            return self.findMedianSortedArrays(nums2, nums1)
        k = (n1 + n2 + 1)//2
        left = 0
        right = n1
        while left < right:
            m1 = left+(right - left)//2
            m2 = k - m1
            if nums1[m1] < nums2[m2 - 1]:
                left = m1 + 1
            else:
                right = m1
        m1 = left
        m2 = k - m1
        c1 = max(nums1[m1 - 1] if m1 > 0 else float("-inf"), nums2[m2 - 1] if m2 > 0 else float("-inf"))
        if (n1 + n2) % 2 == 1:
            return c1
        c2 = min(nums1[m1] if m1 < n1 else float("inf"), nums2[m2] if m2 < n2 else float("inf"))
        return (c1+c2) / 2