71 lines
1.9 KiB
Python
71 lines
1.9 KiB
Python
#coding: utf-8
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''' mbinary
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#######################################################################
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# File : maxXor.py
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# Author: mbinary
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# Mail: zhuheqin1@gmail.com
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# Blog: https://mbinary.xyz
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# Github: https://github.com/mbinary
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# Created Time: 2018-12-22 09:51
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# Description:
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maximum_xor_of_two_numbers_in_an_array:
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using trie data structure
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O(k*n) where n=length(array),k is the max length of radix of num
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#######################################################################
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'''
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class node:
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def __init__(self,key,hasKey = False):
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self.key = key
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self.hasKey = hasKey
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self.children={}
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def __getitem__(self,key):
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return self.children[key]
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def __len__(self):
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return len(self.children)
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def __setitem__(self,key,val):
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self.children[key]=val
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def __contains__(self,key):
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return key in self.children
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class trie:
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def __init__(self,maxDepth=32):
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self.root=node(None)
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self.maxDepth = maxDepth
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def add(self,num):
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nd = self.root
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s = bin(num)[2:].rjust(self.maxDepth,'0')
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for n in s:
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if n not in nd:
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nd[n]=node(n)
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nd=nd[n]
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def search(self,num):
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ret = 0
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nd = self.root
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s = bin(num)[2:].rjust(self.maxDepth,'0')
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for n in s:
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# note that it's the flip bit
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flip = '1' if n=='0' else '0'
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if flip in nd:
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ret=ret*2+1
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nd=nd[flip]
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else:
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ret*=2
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nd=nd[n]
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return ret
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def findMaximumXOR(self, nums):
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"""
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:type nums: List[int]
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:rtype: int
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"""
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if not nums:return 0
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n = len(bin(max(nums)))-1
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t = trie(n)
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for i in nums:t.add(i)
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return max(t.search(i) for i in nums)
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if __name__=='__main__':
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from random import randint
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nums = [randint(1,int(1e18)) for i in 100]
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findMaximumXOR(nums)
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