Python寻找两个有序数组的中位数实例详解

class Solution:
  def findMedianSortedArrays(self, nums1, nums2):
    """
    :type nums1: List[int]
    :type nums2: List[int]
    :rtype: float
    """
    m, n = len(nums1), len(nums2)
    if m > n:
      nums1, nums2, m, n = nums2, nums1, n, m
    if n == 0:
      raise ValueError
    imin, imax, half_len = 0, m, (m + n + 1) // 2
    while imin <= imax:
      i = (imin + imax) // 2
      j = half_len - i
      if i < m and nums2[j-1] > nums1[i]:
        # i is too small, must increase it
        imin = i + 1
      elif i > 0 and nums1[i-1] > nums2[j]:
        # i is too big, must decrease it
        imax = i - 1
      else:
        # i is perfect
        if i == 0: max_of_left = nums2[j-1]
        elif j == 0: max_of_left = nums1[i-1]
        else: max_of_left = max(nums1[i-1], nums2[j-1])
        if (m + n) % 2 == 1:
          return max_of_left
        if i == m: min_of_right = nums2[j]
        elif j == n: min_of_right = nums1[i]
        else: min_of_right = min(nums1[i], nums2[j])
        return (max_of_left + min_of_right) / 2.0