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