[LEET-3289] add 3289

Author: fishercoder1534

Diff for: paginated_contents/algorithms/4th_thousand/README.md

@@ -5,6 +5,7 @@
 | 3314 | [Construct the Minimum Bitwise Array I](https://leetcode.com/problems/construct-the-minimum-bitwise-array-i/)                                                      | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3314.java) |                                                                               | Easy       |
 | 3304 | [Find the K-th Character in String Game I](https://leetcode.com/problems/find-the-k-th-character-in-string-game-i/)                                                | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3304.java) |                                                                               | Easy       |
 | 3300 | [Minimum Element After Replacement With Digit Sum](https://leetcode.com/problems/minimum-element-after-replacement-with-digit-sum/)                                        | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3300java)  |                                                                               | Easy       |
+| 3289 | [The Two Sneaky Numbers of Digitville](https://leetcode.com/problems/the-two-sneaky-numbers-of-digitville/)                                                                | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3289.java) |                                                                               | Easy       |
 | 3285 | [Find Indices of Stable Mountains](https://leetcode.com/problems/find-indices-of-stable-mountains/)                                                                | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3285.java) |                                                                               | Easy       |
 | 3270 | [Find the Key of the Numbers](https://leetcode.com/problems/find-the-key-of-the-numbers/)                      | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3270.java) |                                                                               | Easy       |
 | 3264 | [Final Array State After K Multiplication Operations I](https://leetcode.com/problems/final-array-state-after-k-multiplication-operations-i/)                      | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3264.java) |                                                                               | Easy       |

Diff for: src/main/java/com/fishercoder/solutions/fourththousand/_3289.java

@@ -0,0 +1,20 @@
+package com.fishercoder.solutions.fourththousand;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class _3289 {
+    public static class Solution1 {
+        public int[] getSneakyNumbers(int[] nums) {
+            int[] ans = new int[2];
+            Set<Integer> set = new HashSet<>();
+            int i = 0;
+            for (int num : nums) {
+                if (!set.add(num)) {
+                    ans[i++] = num;
+                }
+            }
+            return ans;
+        }
+    }
+}