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51 lines
1.2 KiB
51 lines
1.2 KiB
2 years ago
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package class06;
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// 本题测试链接 : https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/
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public class Code02_MaximumXorOfTwoNumbersInAnArray {
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public static class Node {
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public Node[] nexts = new Node[2];
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}
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public static class NumTrie {
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public Node head = new Node();
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public void add(int newNum) {
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Node cur = head;
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for (int move = 31; move >= 0; move--) {
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int path = ((newNum >> move) & 1);
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cur.nexts[path] = cur.nexts[path] == null ? new Node() : cur.nexts[path];
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cur = cur.nexts[path];
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}
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}
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public int maxXor(int sum) {
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Node cur = head;
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int res = 0;
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for (int move = 31; move >= 0; move--) {
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int path = (sum >> move) & 1;
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int best = move == 31 ? path : (path ^ 1);
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best = cur.nexts[best] != null ? best : (best ^ 1);
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res |= (path ^ best) << move;
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cur = cur.nexts[best];
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}
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return res;
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}
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}
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public static int findMaximumXOR(int[] arr) {
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if (arr == null || arr.length < 2) {
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return 0;
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}
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int max = Integer.MIN_VALUE;
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NumTrie numTrie = new NumTrie();
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numTrie.add(arr[0]);
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for (int i = 1; i < arr.length; i++) {
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max = Math.max(max, numTrie.maxXor(arr[i]));
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numTrie.add(arr[i]);
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}
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return max;
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}
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}
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