"Leeetcode" 4. Median of Sorted Arrays

There is sorted arrays nums1 and nums2 of size m and N respectively.

Find The median of the sorted arrays. The overall run time complexity should be O (log (m+n)).

Example 1:

NUMS1 = [1, 3]nums2 = [2]the median is 2.0

Example 2:

NUMS1 = [1, 2]NUMS2 = [3, 4]the median is (2 + 3)/2 = 2.5

Test instructions: Finding the median value of two arrays

Idea: First of all, you want to use a method like merge sorting, sorting is done, the median value is selected, but the time complexity is not O (log (m+n))

To find another way out of the web, I write down my own ideas:

Find the middle value, that is, the number of K small

The idea of using the binary lookup method, the K/2 small value in or not in a short array, such as a short array of things nums1.

If K/2 is in a short array, compare NUMS1[K/2] and NUMS2[K/2], such as if NUMS1[K/2] is smaller, then you can exclude all the numbers in Nums1 before the index K/2.

If K/2 is not in a short array, compare the values of Nums1[len (NUMS1)] and Nums2[k-len (NUMS1)], and who is smaller, exclude which array

If two values are equal, they are found!

1 classsolution (object):2     deffindmediansortedarrays (self, NUMS1, NUMS2):3         """4 : Type Nums1:list[int]5 : Type Nums2:list[int]6 : Rtype:float7         """8Len1 =Len (nums1)9Len2 =Len (NUMS2)TenL = len1 +Len2 One         ifl&0x1 = = 1: A             returnSELF.FINDK (nums1,len1,nums2,len2,l/2+1) -         Else: -             return(SELF.FINDK (NUMS1,LEN1,NUMS2,LEN2,L/2) +self.findk (nums1,len1,nums2,len2,l/2+1)) *1.0/2 the      -     deffindk (self,nums1,len1,nums2,len2,k): -         ifLen1>Len2: -             returnself.findk (nums2,len2,nums1,len1,k) +         ifLen1 = =0: -             returnNums2[k-1] +         ifK = = 1: A             returnmin (nums1[0],nums2[0]) atMID = K/2 -PA =min (mid,len1) -PB = KPA -         ifNums1[pa-1] < Nums2[pb-1]: -             returnSELF.FINDK (nums1[pa:],len1-pa,nums2,len2,k-PA) -         elifNums1[pa-1] > Nums2[pb-1]: in             returnSELF.FINDK (nums1,len1,nums2[pb:],len2-pb,k-pb) -         Else: to             returnNums1[pa-1]

"Leeetcode" 4. Median of Sorted Arrays