86 lines
1.2 KiB
Markdown
86 lines
1.2 KiB
Markdown
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---
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layout: page
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title: Maximum XOR of Two Numbers in an Array
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last_solved:
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category: bits
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leetcode_url: https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/
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status: Attempted
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---
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Problem
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-------
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```
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Given a non-empty array of numbers, a0, a1, a2, … , an-1, where 0 ≤ ai < 231.
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Find the maximum result of ai XOR aj, where 0 ≤ i, j < n.
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Could you do this in O(n) runtime?
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Example:
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Input: [3, 10, 5, 25, 2, 8]
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Output: 28
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Explanation: The maximum result is 5 ^ 25 = 28.
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```
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Solution
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----------
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{% highlight python %}
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def findMaximumXOR(self, nums: List[int]) -> int:
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output, mask = 0,0
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for i in range(4,-1,-1):
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mask = mask | (1<<i)
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print(bin(mask))
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found = set([n&mask for n in nums])
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print(found)
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temp = output | 1 << i
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for f in found:
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if f^temp in found:
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output = temp
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return output
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{% endhighlight %}
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______________
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```
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Your input
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[3, 10, 5, 25, 2, 8]
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stdout
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0b10000
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{0, 16}
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0b11000
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{0, 8, 24}
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0b11100
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{0, 8, 4, 24}
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0b11110
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{2, 4, 8, 10, 24}
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0b11111
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{2, 3, 5, 8, 10, 25}
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Output
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28
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```
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![image1]()
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