421.Maximum XOR of Two Numbers in an Array

1

https://kingsfish.github.io/2017/12/15/Leetcode-421-Maximum-XOR-of-Two-Numbers-in-an-Array/

class Solution {
    public int findMaximumXOR(int[] nums) {
        int max = 0;
        int mask = 0;
        for(int i = 31; i >= 0; i--){
            mask = mask | (1 << i);
            Set<Integer> set = new HashSet<>();
            for(int num : nums){
                set.add(num & mask);
            }
            int tmp = max | (1 << i);
            for(int prefix : set){
                if(set.contains(tmp ^ prefix)){
                    max = tmp;
                    break;
                }
            }
        }
        return max;
    }
}