You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
51 lines
1.2 KiB
51 lines
1.2 KiB
package class06;
|
|
|
|
// 本题测试链接 : https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/
|
|
public class Code02_MaximumXorOfTwoNumbersInAnArray {
|
|
|
|
public static class Node {
|
|
public Node[] nexts = new Node[2];
|
|
}
|
|
|
|
public static class NumTrie {
|
|
public Node head = new Node();
|
|
|
|
public void add(int newNum) {
|
|
Node cur = head;
|
|
for (int move = 31; move >= 0; move--) {
|
|
int path = ((newNum >> move) & 1);
|
|
cur.nexts[path] = cur.nexts[path] == null ? new Node() : cur.nexts[path];
|
|
cur = cur.nexts[path];
|
|
}
|
|
}
|
|
|
|
public int maxXor(int sum) {
|
|
Node cur = head;
|
|
int res = 0;
|
|
for (int move = 31; move >= 0; move--) {
|
|
int path = (sum >> move) & 1;
|
|
int best = move == 31 ? path : (path ^ 1);
|
|
best = cur.nexts[best] != null ? best : (best ^ 1);
|
|
res |= (path ^ best) << move;
|
|
cur = cur.nexts[best];
|
|
}
|
|
return res;
|
|
}
|
|
}
|
|
|
|
public static int findMaximumXOR(int[] arr) {
|
|
if (arr == null || arr.length < 2) {
|
|
return 0;
|
|
}
|
|
int max = Integer.MIN_VALUE;
|
|
NumTrie numTrie = new NumTrie();
|
|
numTrie.add(arr[0]);
|
|
for (int i = 1; i < arr.length; i++) {
|
|
max = Math.max(max, numTrie.maxXor(arr[i]));
|
|
numTrie.add(arr[i]);
|
|
}
|
|
return max;
|
|
}
|
|
|
|
}
|