Added tasks 39-46

Author: ThanhNIT

README.md

@@ -84,6 +84,7 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0046 |[Permutations](src/main/js/g0001_0100/s0046_permutations/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n\*n!)_Space_O(n+n!) | 0 | 100.00
 
 #### Day 12 Dynamic Programming
 
@@ -155,6 +156,7 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0039 |[Combination Sum](src/main/js/g0001_0100/s0039_combination_sum/solution.js)| Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 1 | 98.51
 
 #### Day 11 Recursion Backtracking
 
@@ -172,6 +174,7 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0045 |[Jump Game II](src/main/js/g0001_0100/s0045_jump_game_ii/solution.js)| Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
 
 #### Day 14 Dynamic Programming
 
@@ -402,6 +405,7 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0045 |[Jump Game II](src/main/js/g0001_0100/s0045_jump_game_ii/solution.js)| Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
 
 #### Day 5
 
@@ -427,6 +431,7 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0042 |[Trapping Rain Water](src/main/js/g0001_0100/s0042_trapping_rain_water/solution.js)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
 
 #### Day 10
 
@@ -961,6 +966,8 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
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+| 0039 |[Combination Sum](src/main/js/g0001_0100/s0039_combination_sum/solution.js)| Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 1 | 98.51
+| 0046 |[Permutations](src/main/js/g0001_0100/s0046_permutations/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n\*n!)_Space_O(n+n!) | 0 | 100.00
 
 ### Udemy
 
@@ -990,11 +997,13 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
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 | 0001 |[Two Sum](src/main/js/g0001_0100/s0001_two_sum/solution.js)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n), AI_can_be_used_to_solve_the_task | 1 | 89.15
+| 0041 |[First Missing Positive](src/main/js/g0001_0100/s0041_first_missing_positive/solution.js)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) | 1 | 98.86
 
 #### Udemy Two Pointers
 
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+| 0042 |[Trapping Rain Water](src/main/js/g0001_0100/s0042_trapping_rain_water/solution.js)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
 | 0015 |[3Sum](src/main/js/g0001_0100/s0015_3sum/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n\*log(n))_Space_O(n^2) | 31 | 91.92
 
 #### Udemy Famous Algorithm
@@ -1046,7 +1055,9 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
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 | 0022 |[Generate Parentheses](src/main/js/g0001_0100/s0022_generate_parentheses/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n) | 0 | 100.00
+| 0039 |[Combination Sum](src/main/js/g0001_0100/s0039_combination_sum/solution.js)| Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 1 | 98.51
 | 0017 |[Letter Combinations of a Phone Number](src/main/js/g0001_0100/s0017_letter_combinations_of_a_phone_number/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n) | 0 | 100.00
+| 0046 |[Permutations](src/main/js/g0001_0100/s0046_permutations/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n\*n!)_Space_O(n+n!) | 0 | 100.00
 
 #### Udemy Bit Manipulation
 
@@ -1249,6 +1260,11 @@ JavaScript-based LeetCode algorithm problem solutions, regularly updated.
 
 | #    |      Title     | Difficulty  | Tag         | Time, ms | Time, %
 |------|----------------|-------------|-------------|----------|---------
+| 0046 |[Permutations](src/main/js/g0001_0100/s0046_permutations/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Algorithm_I_Day_11_Recursion_Backtracking, Level_2_Day_20_Brute_Force/Backtracking, Udemy_Backtracking/Recursion, Big_O_Time_O(n\*n!)_Space_O(n+n!) | 0 | 100.00
+| 0045 |[Jump Game II](src/main/js/g0001_0100/s0045_jump_game_ii/solution.js)| Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Algorithm_II_Day_13_Dynamic_Programming, Dynamic_Programming_I_Day_4, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
+| 0042 |[Trapping Rain Water](src/main/js/g0001_0100/s0042_trapping_rain_water/solution.js)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Dynamic_Programming_I_Day_9, Udemy_Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 0 | 100.00
+| 0041 |[First Missing Positive](src/main/js/g0001_0100/s0041_first_missing_positive/solution.js)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Udemy_Arrays, Big_O_Time_O(n)_Space_O(n) | 1 | 98.86
+| 0039 |[Combination Sum](src/main/js/g0001_0100/s0039_combination_sum/solution.js)| Medium | Top_100_Liked_Questions, Array, Backtracking, Algorithm_II_Day_10_Recursion_Backtracking, Level_2_Day_20_Brute_Force/Backtracking, Udemy_Backtracking/Recursion, Big_O_Time_O(2^n)_Space_O(n+2^n) | 1 | 98.51
 | 0035 |[Search Insert Position](src/main/js/g0001_0100/s0035_search_insert_position/solution.js)| Easy | Top_100_Liked_Questions, Array, Binary_Search, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_2, Big_O_Time_O(log_n)_Space_O(1) | 0 | 100.00
 | 0034 |[Find First and Last Position of Element in Sorted Array](src/main/js/g0001_0100/s0034_find_first_and_last_position_of_element_in_sorted_array/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Algorithm_II_Day_1_Binary_Search, Binary_Search_I_Day_5, Big_O_Time_O(log_n)_Space_O(1) | 0 | 100.00
 | 0033 |[Search in Rotated Sorted Array](src/main/js/g0001_0100/s0033_search_in_rotated_sorted_array/solution.js)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Algorithm_II_Day_1_Binary_Search, Binary_Search_I_Day_11, Level_2_Day_8_Binary_Search, Udemy_Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 0 | 100.00

src/main/js/g0001_0100/s0039_combination_sum/readme.md

@@ -0,0 +1,41 @@
+39\. Combination Sum
+
+Medium
+
+Given an array of **distinct** integers `candidates` and a target integer `target`, return _a list of all **unique combinations** of_ `candidates` _where the chosen numbers sum to_ `target`_._ You may return the combinations in **any order**.
+
+The **same** number may be chosen from `candidates` an **unlimited number of times**. Two combinations are unique if the frequency of at least one of the chosen numbers is different.
+
+It is **guaranteed** that the number of unique combinations that sum up to `target` is less than `150` combinations for the given input.
+
+**Example 1:**
+
+**Input:** candidates = [2,3,6,7], target = 7
+
+**Output:** [[2,2,3],[7]]
+
+**Explanation:** 
+2 and 3 are candidates, and 2 + 2 + 3 = 7. Note that 2 can be used multiple times.
+
+7 is a candidate, and 7 = 7. 
+
+These are the only two combinations.
+
+**Example 2:**
+
+**Input:** candidates = [2,3,5], target = 8
+
+**Output:** [[2,2,2,2],[2,3,3],[3,5]]
+
+**Example 3:**
+
+**Input:** candidates = [2], target = 1
+
+**Output:** []
+
+**Constraints:**
+
+*   `1 <= candidates.length <= 30`
+*   `1 <= candidates[i] <= 200`
+*   All elements of `candidates` are **distinct**.
+*   `1 <= target <= 500`

src/main/js/g0001_0100/s0039_combination_sum/solution.js

@@ -0,0 +1,35 @@
+// #Medium #Top_100_Liked_Questions #Array #Backtracking #Algorithm_II_Day_10_Recursion_Backtracking
+// #Level_2_Day_20_Brute_Force/Backtracking #Udemy_Backtracking/Recursion
+// #Big_O_Time_O(2^n)_Space_O(n+2^n) #2024_12_08_Time_1_ms_(98.51%)_Space_54.6_MB_(59.25%)
+
+/**
+ * @param {number[]} candidates
+ * @param {number} target
+ * @return {number[][]}
+ */
+var combinationSum = function(candidates, target) {
+    const ans = []
+    const subList = []
+
+    const combinationSumRec = (n, candidates, target, subList, ans) => {
+        if (target === 0 || n === 0) {
+            if (target === 0) {
+                ans.push([...subList]) // Create a copy of subList
+            }
+            return
+        }
+
+        if (target - candidates[n - 1] >= 0) {
+            subList.push(candidates[n - 1])
+            combinationSumRec(n, candidates, target - candidates[n - 1], subList, ans)
+            subList.pop() // Backtracking step
+        }
+
+        combinationSumRec(n - 1, candidates, target, subList, ans)
+    }
+
+    combinationSumRec(candidates.length, candidates, target, subList, ans)
+    return ans
+};
+
+export { combinationSum }

src/main/js/g0001_0100/s0041_first_missing_positive/readme.md

@@ -0,0 +1,36 @@
+41\. First Missing Positive
+
+Hard
+
+Given an unsorted integer array `nums`, return the smallest missing positive integer.
+
+You must implement an algorithm that runs in `O(n)` time and uses constant extra space.
+
+**Example 1:**
+
+**Input:** nums = [1,2,0]
+
+**Output:** 3
+
+**Explanation:** The numbers in the range [1,2] are all in the array.
+
+**Example 2:**
+
+**Input:** nums = [3,4,-1,1]
+
+**Output:** 2
+
+**Explanation:** 1 is in the array but 2 is missing.
+
+**Example 3:**
+
+**Input:** nums = [7,8,9,11,12]
+
+**Output:** 1
+
+**Explanation:** The smallest positive integer 1 is missing.
+
+**Constraints:**
+
+*   <code>1 <= nums.length <= 10<sup>5</sup></code>
+*   <code>-2<sup>31</sup> <= nums[i] <= 2<sup>31</sup> - 1</code>

src/main/js/g0001_0100/s0041_first_missing_positive/solution.js

@@ -0,0 +1,31 @@
+// #Hard #Top_100_Liked_Questions #Top_Interview_Questions #Array #Hash_Table #Udemy_Arrays
+// #Big_O_Time_O(n)_Space_O(n) #2024_12_08_Time_1_ms_(98.86%)_Space_56.6_MB_(89.65%)
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var firstMissingPositive = function(nums) {
+    for (let i = 0; i < nums.length; i++) {
+        while (
+            nums[i] > 0 &&
+            nums[i] <= nums.length &&
+            nums[nums[i] - 1] !== nums[i]
+        ) {
+            // Swap nums[i] with nums[nums[i] - 1]
+            let temp = nums[nums[i] - 1]
+            nums[nums[i] - 1] = nums[i]
+            nums[i] = temp
+        }
+    }
+
+    for (let i = 0; i < nums.length; i++) {
+        if (nums[i] !== i + 1) {
+            return i + 1
+        }
+    }
+
+    return nums.length + 1
+};
+
+export { firstMissingPositive }

src/main/js/g0001_0100/s0042_trapping_rain_water/readme.md

@@ -0,0 +1,27 @@
+42\. Trapping Rain Water
+
+Hard
+
+Given `n` non-negative integers representing an elevation map where the width of each bar is `1`, compute how much water it can trap after raining.
+
+**Example 1:**
+
+![](https://assets.leetcode.com/uploads/2018/10/22/rainwatertrap.png)
+
+**Input:** height = [0,1,0,2,1,0,1,3,2,1,2,1]
+
+**Output:** 6
+
+**Explanation:** The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped.
+
+**Example 2:**
+
+**Input:** height = [4,2,0,3,2,5]
+
+**Output:** 9
+
+**Constraints:**
+
+*   `n == height.length`
+*   <code>1 <= n <= 2 * 10<sup>4</sup></code>
+*   <code>0 <= height[i] <= 10<sup>5</sup></code>

src/main/js/g0001_0100/s0042_trapping_rain_water/solution.js

@@ -0,0 +1,40 @@
+// #Hard #Top_100_Liked_Questions #Top_Interview_Questions #Array #Dynamic_Programming #Two_Pointers
+// #Stack #Monotonic_Stack #Dynamic_Programming_I_Day_9 #Udemy_Two_Pointers
+// #Big_O_Time_O(n)_Space_O(1) #2024_12_08_Time_0_ms_(100.00%)_Space_51.2_MB_(88.05%)
+
+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+var trap = function(height) {
+    let l = 0
+    let r = height.length - 1
+    let res = 0
+    let lowerWall = 0
+
+    while (l < r) {
+        let lVal = height[l]
+        let rVal = height[r]
+
+        // Determine the lower wall
+        if (lVal < rVal) {
+            // Update the lower wall based on the left pointer
+            lowerWall = Math.max(lVal, lowerWall)
+            // Add water trapped at the current position
+            res += lowerWall - lVal
+            // Move the left pointer
+            l++
+        } else {
+            // Update the lower wall based on the right pointer
+            lowerWall = Math.max(rVal, lowerWall)
+            // Add water trapped at the current position
+            res += lowerWall - rVal
+            // Move the right pointer
+            r--
+        }
+    }
+
+    return res
+};
+
+export { trap }

src/main/js/g0001_0100/s0045_jump_game_ii/readme.md

@@ -0,0 +1,30 @@
+45\. Jump Game II
+
+Medium
+
+Given an array of non-negative integers `nums`, you are initially positioned at the first index of the array.
+
+Each element in the array represents your maximum jump length at that position.
+
+Your goal is to reach the last index in the minimum number of jumps.
+
+You can assume that you can always reach the last index.
+
+**Example 1:**
+
+**Input:** nums = [2,3,1,1,4]
+
+**Output:** 2
+
+**Explanation:** The minimum number of jumps to reach the last index is 2. Jump 1 step from index 0 to 1, then 3 steps to the last index.
+
+**Example 2:**
+
+**Input:** nums = [2,3,0,1,4]
+
+**Output:** 2
+
+**Constraints:**
+
+*   <code>1 <= nums.length <= 10<sup>4</sup></code>
+*   `0 <= nums[i] <= 1000`

src/main/js/g0001_0100/s0045_jump_game_ii/solution.js

@@ -0,0 +1,32 @@
+// #Medium #Top_100_Liked_Questions #Array #Dynamic_Programming #Greedy
+// #Algorithm_II_Day_13_Dynamic_Programming #Dynamic_Programming_I_Day_4
+// #Big_O_Time_O(n)_Space_O(1) #2024_12_08_Time_0_ms_(100.00%)_Space_51.5_MB_(23.51%)
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var getMax = function(nums, l, r) {
+    let max = -1
+    for (let i = l; i <= r; i++) {
+        max = Math.max(max, i + nums[i])
+    }
+    return max
+};
+
+var jump = function(nums) {
+    let l = 0
+    let r = 0
+    let jumps = 0
+
+    while (r < nums.length - 1) {
+        let prev = r
+        r = getMax(nums, l, r)
+        l = prev + 1
+        jumps++
+    }
+
+    return jumps
+};
+
+export { jump }

src/main/js/g0001_0100/s0046_permutations/readme.md

@@ -0,0 +1,29 @@
+46\. Permutations
+
+Medium
+
+Given an array `nums` of distinct integers, return _all the possible permutations_. You can return the answer in **any order**.
+
+**Example 1:**
+
+**Input:** nums = [1,2,3]
+
+**Output:** [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
+
+**Example 2:**
+
+**Input:** nums = [0,1]
+
+**Output:** [[0,1],[1,0]]
+
+**Example 3:**
+
+**Input:** nums = [1]
+
+**Output:** [[1]]
+
+**Constraints:**
+
+*   `1 <= nums.length <= 6`
+*   `-10 <= nums[i] <= 10`
+*   All the integers of `nums` are **unique**.