diff --git a/src/main/java/leetcode/editor/cn/MaximumXorOfTwoNumbersInAnArray.java b/src/main/java/leetcode/editor/cn/MaximumXorOfTwoNumbersInAnArray.java
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+//给你一个整数数组 nums ，返回 nums[i] XOR nums[j] 的最大运算结果，其中 0 ≤ i ≤ j < n 。 
+//
+// 进阶：你可以在 O(n) 的时间解决这个问题吗？ 
+//
+// 
+//
+// 
+// 
+// 示例 1： 
+//
+// 
+//输入：nums = [3,10,5,25,2,8]
+//输出：28
+//解释：最大运算结果是 5 XOR 25 = 28. 
+//
+// 示例 2： 
+//
+// 
+//输入：nums = [0]
+//输出：0
+// 
+//
+// 示例 3： 
+//
+// 
+//输入：nums = [2,4]
+//输出：6
+// 
+//
+// 示例 4： 
+//
+// 
+//输入：nums = [8,10,2]
+//输出：10
+// 
+//
+// 示例 5： 
+//
+// 
+//输入：nums = [14,70,53,83,49,91,36,80,92,51,66,70]
+//输出：127
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 1 <= nums.length <= 2 * 104 
+// 0 <= nums[i] <= 231 - 1 
+// 
+// 
+// 
+// Related Topics 位运算 字典树 
+// 👍 324 👎 0
+
+package leetcode.editor.cn;
+
+import java.util.HashSet;
+import java.util.Set;
+
+//421:数组中两个数的最大异或值
+public class MaximumXorOfTwoNumbersInAnArray {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new MaximumXorOfTwoNumbersInAnArray().new Solution();
+        System.out.println();
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        public int findMaximumXOR(int[] nums) {
+            int x = 0;
+            for (int k = 30; k >= 0; k--) {
+                Set<Integer> set = new HashSet<>();
+                boolean found = false;
+
+                for (int num : nums) {
+                    set.add(num >> k);
+                    if (set.contains(((x << 1) + 1) ^ (num >> k))) {
+                        found = true;
+                        break;
+                    }
+                }
+
+                x <<= 1;
+                if (found) {
+                    x++;
+                }
+            }
+            return x;
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}
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diff --git a/src/main/java/leetcode/editor/cn/MaximumXorOfTwoNumbersInAnArray.md b/src/main/java/leetcode/editor/cn/MaximumXorOfTwoNumbersInAnArray.md
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+<p>给你一个整数数组 <code>nums</code> ，返回<em> </em><code>nums[i] XOR nums[j]</code> 的最大运算结果，其中 <code>0 ≤ i ≤ j < n</code> 。</p>
+
+<p><strong>进阶：</strong>你可以在 <code>O(n)</code> 的时间解决这个问题吗？</p>
+
+<p> </p>
+
+<div class="original__bRMd">
+<div>
+<p><strong>示例 1：</strong></p>
+
+<pre>
+<strong>输入：</strong>nums = [3,10,5,25,2,8]
+<strong>输出：</strong>28
+<strong>解释：</strong>最大运算结果是 5 XOR 25 = 28.</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>nums = [0]
+<strong>输出：</strong>0
+</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<strong>输入：</strong>nums = [2,4]
+<strong>输出：</strong>6
+</pre>
+
+<p><strong>示例 4：</strong></p>
+
+<pre>
+<strong>输入：</strong>nums = [8,10,2]
+<strong>输出：</strong>10
+</pre>
+
+<p><strong>示例 5：</strong></p>
+
+<pre>
+<strong>输入：</strong>nums = [14,70,53,83,49,91,36,80,92,51,66,70]
+<strong>输出：</strong>127
+</pre>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>1 <= nums.length <= 2 * 10<sup>4</sup></code></li>
+	<li><code>0 <= nums[i] <= 2<sup>31</sup> - 1</code></li>
+</ul>
+</div>
+</div>
+<div><div>Related Topics</div><div><li>位运算</li><li>字典树</li></div></div>\n<div><li>👍 316</li><li>👎 0</li></div>
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