leetcode_gym/_problems/maxXorOfTwoNums.md

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layout	title	last_solved	category	leetcode_url	status
page	Maximum XOR of Two Numbers in an Array		bits	https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/	Attempted

Problem

Given a non-empty array of numbers, a0, a1, a2, … , an-1, where 0 ≤ ai < 231.

Find the maximum result of ai XOR aj, where 0 ≤ i, j < n.

Could you do this in O(n) runtime?

Example:

Input: [3, 10, 5, 25, 2, 8]

Output: 28

Explanation: The maximum result is 5 ^ 25 = 28.

Solution

{% highlight python %}

def findMaximumXOR(self, nums: List[int]) -> int:
    
    output, mask = 0,0
    
    for i in range(4,-1,-1):
        
        mask = mask | (1<<i)
        
        print(bin(mask))
        
        
        found = set([n&mask for n in nums])
        print(found)
        
        temp = output | 1 << i
        for f in found:
            if f^temp in found:
                output = temp
    
    return output

{% endhighlight %}

---

Your input
[3, 10, 5, 25, 2, 8]

stdout
0b10000
{0, 16}
0b11000
{0, 8, 24}
0b11100
{0, 8, 4, 24}
0b11110
{2, 4, 8, 10, 24}
0b11111
{2, 3, 5, 8, 10, 25}

Output
28