Add new problem

Author: Sanajit Jana

README.md

@@ -63,5 +63,5 @@ This repository is licensed under the [MIT License](LICENSE).
 
 ## 🏆 Progress
 
-- Problems solved: 38
-- Last updated: 30 Oct 2025, 05:25 PM UTC+05:30
+- Problems solved: 39
+- Last updated: 31 Oct 2025, 09:28 AM UTC+05:30

p/3289-the-two-sneaky-numbers-of-digitville/README.md

@@ -0,0 +1,99 @@
+# [3289. The Two Sneaky Numbers of Digitville](https://leetcode.com/problems/the-two-sneaky-numbers-of-digitville/description/)
+
+## Question Description
+In the town of Digitville, there was a list of numbers called nums containing integers from 0 to n - 1. Each number was supposed to appear exactly once in the list, however, two mischievous numbers sneaked in an additional time, making the list longer than usual.
+
+As the town detective, your task is to find these two sneaky numbers. Return an array of size two containing the two numbers (in any order), so peace can return to Digitville.
+
+---
+
+## Constraints
+- 2 <= n <= 100
+- nums.length == n + 2
+- 0 <= nums[i] < n
+- The input is generated such that nums contains exactly two repeated elements.
+
+---
+
+## Solution 1: Sorting Approach
+
+### Approach
+Sort the array and iterate through it to find consecutive duplicates, as the duplicates will be adjacent after sorting.
+
+### Dry Run
+Example Input: nums = [0,1,1,0]
+
+Sorted: [0,0,1,1]
+
+Iterate:
+- i=0: nums[0]=0 == nums[1]=0, add 0, i+=2 to 2
+- i=2: nums[2]=1 == nums[3]=1, add 1, i+=2 to 4
+
+Answer: [0,1]
+
+### Code
+```java
+class Solution {
+    public int[] getSneakyNumbers(int[] nums) {
+        Arrays.sort(nums);
+        int[] ans = new int[2];
+        int index = 0;
+        for (int i = 0; i < nums.length - 1; i++) {
+            if (nums[i] == nums[i + 1]) {
+                ans[index++] = nums[i];
+                i++;
+            }
+            if (index == 2) {
+                break;
+            }
+        }
+        return ans;
+    }
+}
+```
+
+### Time and Space Complexity
+- **Time Complexity:** O(n log n) due to sorting
+- **Space Complexity:** O(1) extra space (sorting in place)
+
+---
+
+## Solution 2: HashMap Approach
+
+### Approach
+Use a HashMap to count the frequency of each number, then iterate through the map to find numbers with count >= 2.
+
+### Dry Run
+Example Input: nums = [0,1,1,0]
+
+Map after counting: {0:2, 1:2}
+
+Iterate map entries:
+- 0 has count 2, add 0
+- 1 has count 2, add 1
+
+Answer: [0,1]
+
+### Code
+```java
+class Solution {
+    public int[] getSneakyNumbers(int[] nums) {
+        HashMap<Integer, Integer> map = new HashMap<>();
+        for (int num : nums) {
+            map.put(num, map.getOrDefault(num, 0) + 1);
+        }
+        int[] ans = new int[2];
+        int index = 0;
+        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
+            if (entry.getValue() >= 2) {
+                ans[index++] = entry.getKey();
+            }
+        }
+        return ans;
+    }
+}
+```
+
+### Time and Space Complexity
+- **Time Complexity:** O(n)
+- **Space Complexity:** O(n) for the HashMap

p/README.md

@@ -16,44 +16,32 @@
 
 0342: Power of Four - [`0342-power-of-four/`](0342-power-of-four/)
 
-0812: Largest Triangle Area - [`0812-largest-triangle-area/`](0812-largest-triangle-area/)
-
-1323: Maximum 69 Number - [`1323-maximum-69-number/`](1323-maximum-69-number/)
+0611: Valid Triangle Number - [`0611-valid-triangle-number/`](0611-valid-triangle-number/)
 
-2264: Largest 3-Same-Digit Number in String - [`2264-largest-3-same-digit-number-in-string/`](2264-largest-3-same-digit-number-in-string/)
+0812: Largest Triangle Area - [`0812-largest-triangle-area/`](0812-largest-triangle-area/)
 
 0830: Positions of Large Groups - [`0830-positions-of-large-groups/`](0830-positions-of-large-groups/)
 
+0966: Vowel Spellchecker - [`0966-vowel-spellchecker/`](0966-vowel-spellchecker/)
+
 0976: Largest Perimeter Triangle - [`0976-largest-perimeter-triangle/`](0976-largest-perimeter-triangle/)
 
 1304: Find N Unique Integers Sum up to Zero - [`1304-find-n-unique-integers-sum-up-to-zero/`](1304-find-n-unique-integers-sum-up-to-zero/)
 
-1796: Second Largest Digit in a String - [`1796-second-largest-digit-in-a-string/`](1796-second-largest-digit-in-a-string/)
-
-2016: Maximum Difference Between Increasing Elements - [`2016-maximum-difference-between-increasing-elements/`](2016-maximum-difference-between-increasing-elements/)
-
-2942: Find Words Containing Character - [`2942-find-words-containing-character/`](2942-find-words-containing-character/)
-
-3024: Type of Triangle - [`3024-type-of-triangle/`](3024-type-of-triangle/)
-
-3688: Bitwise OR of Even Numbers in an Array - [`3688-bitwise-or-of-even-numbers-in-an-array/`](3688-bitwise-or-of-even-numbers-in-an-array/)
-
-3697: Compute Decimal Representation - [`3697-compute-decimal-representation/`](3697-compute-decimal-representation/)
-
-3005: Count Elements With Maximum Frequency - [`3005-count-elements-with-maximum-frequency/`](3005-count-elements-with-maximum-frequency/)
-
-3069: Distribute Elements Into Two Arrays I - [`3069-distribute-elements-into-two-arrays-i/`](3069-distribute-elements-into-two-arrays-i/)
-
-0611: Valid Triangle Number - [`0611-valid-triangle-number/`](0611-valid-triangle-number/)
-
-0966: Vowel Spellchecker - [`0966-vowel-spellchecker/`](0966-vowel-spellchecker/)
+1323: Maximum 69 Number - [`1323-maximum-69-number/`](1323-maximum-69-number/)
 
 1518: Water Bottles - [`1518-water-bottles/`](1518-water-bottles/)
 
 1535: Find the Winner of an Array Game - [`1535-find-the-winner-of-an-array-game/`](1535-find-the-winner-of-an-array-game/)
 
 1733: Minimum Number of People to Teach - [`1733-minimum-number-of-people-to-teach/`](1733-minimum-number-of-people-to-teach/)
 
+1796: Second Largest Digit in a String - [`1796-second-largest-digit-in-a-string/`](1796-second-largest-digit-in-a-string/)
+
+2016: Maximum Difference Between Increasing Elements - [`2016-maximum-difference-between-increasing-elements/`](2016-maximum-difference-between-increasing-elements/)
+
+2264: Largest 3-Same-Digit Number in String - [`2264-largest-3-same-digit-number-in-string/`](2264-largest-3-same-digit-number-in-string/)
+
 2300: Successful Pairs of Spells and Potions - [`2300-successful-pairs-of-spells-and-potions/`](2300-successful-pairs-of-spells-and-potions/)
 
 2348: Number of Zero Filled Subarrays - [`2348-number-of-zero-filled-subarrays/`](2348-number-of-zero-filled-subarrays/)
@@ -62,14 +50,28 @@
 
 2785: Sort Vowels in a String - [`2785-sort-vowels-in-a-string/`](2785-sort-vowels-in-a-string/)
 
+2942: Find Words Containing Character - [`2942-find-words-containing-character/`](2942-find-words-containing-character/)
+
+3005: Count Elements With Maximum Frequency - [`3005-count-elements-with-maximum-frequency/`](3005-count-elements-with-maximum-frequency/)
+
 3021: Alice and Bob Playing Flower Game - [`3021-alice-and-bob-playing-flower-game/`](3021-alice-and-bob-playing-flower-game/)
 
+3024: Type of Triangle - [`3024-type-of-triangle/`](3024-type-of-triangle/)
+
+3069: Distribute Elements Into Two Arrays I - [`3069-distribute-elements-into-two-arrays-i/`](3069-distribute-elements-into-two-arrays-i/)
+
 3227: Vowels Game in a String - [`3227-vowels-game-in-a-string/`](3227-vowels-game-in-a-string/)
 
+3289: The Two Sneaky Numbers of Digitville - [`3289-the-two-sneaky-numbers-of-digitville/`](3289-the-two-sneaky-numbers-of-digitville/)
+
 3408: Design Task Manager - [`3408-design-task-manager/`](3408-design-task-manager/)
 
 3484: Design Spreadsheet - [`3484-design-spreadsheet/`](3484-design-spreadsheet/)
 
+3688: Bitwise OR of Even Numbers in an Array - [`3688-bitwise-or-of-even-numbers-in-an-array/`](3688-bitwise-or-of-even-numbers-in-an-array/)
+
 3689: Maximum Total Subarray Value I - [`3689-maximum-total-subarray-value-i/`](3689-maximum-total-subarray-value-i/)
 
+3697: Compute Decimal Representation - [`3697-compute-decimal-representation/`](3697-compute-decimal-representation/)
+
 3698: Split Array With Minimum Difference - [`3698-split-array-with-minimum-difference/`](3698-split-array-with-minimum-difference/)