Added task 3716

javadev · javadev · commit 5f00ef6f2edc · 2025-10-19T04:33:17.000+03:00
diff --git a/README.md b/README.md
@@ -2088,6 +2088,7 @@
 
 | #    |      Title     | Difficulty  | Tag         | Time, ms | Time, %
 |------|----------------|-------------|-------------|----------|---------
+| 3716 |[Find Churn Risk Customers](src/main/kotlin/g3701_3800/s3716_find_churn_risk_customers)| Medium | Database | 256 | 96.87
 | 3715 |[Sum of Perfect Square Ancestors](src/main/kotlin/g3701_3800/s3715_sum_of_perfect_square_ancestors)| Hard | Array, Hash_Table, Math, Depth_First_Search, Tree, Counting, Number_Theory, Weekly_Contest_471 | 148 | 100.00
 | 3714 |[Longest Balanced Substring II](src/main/kotlin/g3701_3800/s3714_longest_balanced_substring_ii)| Medium | String, Hash_Table, Prefix_Sum, Weekly_Contest_471 | 194 | 100.00
 | 3713 |[Longest Balanced Substring I](src/main/kotlin/g3701_3800/s3713_longest_balanced_substring_i)| Medium | String, Hash_Table, Counting, Enumeration, Weekly_Contest_471 | 35 | 100.00
@@ -2867,7 +2868,7 @@
 | 2730 |[Find the Longest Semi-Repetitive Substring](src/main/kotlin/g2701_2800/s2730_find_the_longest_semi_repetitive_substring)| Medium | String, Sliding_Window | 251 | 84.62
 | 2729 |[Check if The Number is Fascinating](src/main/kotlin/g2701_2800/s2729_check_if_the_number_is_fascinating)| Easy | Hash_Table, Math | 131 | 100.00
 | 2727 |[Is Object Empty](src/main/kotlin/g2701_2800/s2727_is_object_empty)| Easy || 49 | 98.24
-| 2726 |[Calculator with Method Chaining](src/main/kotlin/g2701_2800/s2726_calculator_with_method_chaining)| Easy || 43 | 99.15
+| 2726 |[Calculator with Method Chaining](src/main/kotlin/g2701_2800/s2726_calculator_with_method_chaining)| Easy || 39 | 99.67
 | 2725 |[Interval Cancellation](src/main/kotlin/g2701_2800/s2725_interval_cancellation)| Easy || 51 | 98.87
 | 2724 |[Sort By](src/main/kotlin/g2701_2800/s2724_sort_by)| Easy || 132 | 96.70
 | 2723 |[Add Two Promises](src/main/kotlin/g2701_2800/s2723_add_two_promises)| Easy || 56 | 97.63
@@ -2886,15 +2887,15 @@
 | 2708 |[Maximum Strength of a Group](src/main/kotlin/g2701_2800/s2708_maximum_strength_of_a_group)| Medium | Array, Sorting, Greedy, Backtracking | 183 | 100.00
 | 2707 |[Extra Characters in a String](src/main/kotlin/g2701_2800/s2707_extra_characters_in_a_string)| Medium | Array, String, Hash_Table, Dynamic_Programming, Trie | 276 | 85.71
 | 2706 |[Buy Two Chocolates](src/main/kotlin/g2701_2800/s2706_buy_two_chocolates)| Easy | Array, Sorting | 187 | 96.43
-| 2705 |[Compact Object](src/main/kotlin/g2701_2800/s2705_compact_object)| Medium || 78 | 99.38
+| 2705 |[Compact Object](src/main/kotlin/g2701_2800/s2705_compact_object)| Medium || 80 | 88.30
 | 2704 |[To Be Or Not To Be](src/main/kotlin/g2701_2800/s2704_to_be_or_not_to_be)| Easy || 49 | 97.88
 | 2703 |[Return Length of Arguments Passed](src/main/kotlin/g2701_2800/s2703_return_length_of_arguments_passed)| Easy || 47 | 98.59
 | 2699 |[Modify Graph Edge Weights](src/main/kotlin/g2601_2700/s2699_modify_graph_edge_weights)| Hard | Heap_Priority_Queue, Graph, Shortest_Path | 1592 | 40.00
 | 2698 |[Find the Punishment Number of an Integer](src/main/kotlin/g2601_2700/s2698_find_the_punishment_number_of_an_integer)| Medium | Math, Backtracking | 133 | 100.00
 | 2697 |[Lexicographically Smallest Palindrome](src/main/kotlin/g2601_2700/s2697_lexicographically_smallest_palindrome)| Easy | String, Two_Pointers | 267 | 100.00
 | 2696 |[Minimum String Length After Removing Substrings](src/main/kotlin/g2601_2700/s2696_minimum_string_length_after_removing_substrings)| Easy | String, Stack, Simulation | 185 | 100.00
 | 2695 |[Array Wrapper](src/main/kotlin/g2601_2700/s2695_array_wrapper)| Easy || 40 | 100.00
-| 2694 |[Event Emitter](src/main/kotlin/g2601_2700/s2694_event_emitter)| Medium || 45 | 99.58
+| 2694 |[Event Emitter](src/main/kotlin/g2601_2700/s2694_event_emitter)| Medium || 50 | 90.72
 | 2693 |[Call Function with Custom Context](src/main/kotlin/g2601_2700/s2693_call_function_with_custom_context)| Medium | Array, Dynamic_Programming, Matrix | 51 | 97.92
 | 2685 |[Count the Number of Complete Components](src/main/kotlin/g2601_2700/s2685_count_the_number_of_complete_components)| Medium | Array, Dynamic_Programming, Depth_First_Search, Breadth_First_Search, Matrix, Graph | 436 | 100.00
 | 2684 |[Maximum Number of Moves in a Grid](src/main/kotlin/g2601_2700/s2684_maximum_number_of_moves_in_a_grid)| Medium | Array, Dynamic_Programming, Matrix | 509 | 100.00
diff --git a/src/main/kotlin/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/readme.md b/src/main/kotlin/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/readme.md
@@ -13,31 +13,36 @@ Return _the_ `head` _of the flattened list. The nodes in the list must have **al
 
 **Example 1:**
 
-![](https://assets.leetcode.com/uploads/2021/11/09/flatten11.jpg)
+![](https://leetcode-images.github.io/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/flatten11.jpg)
 
 **Input:** head = [1,2,3,4,5,6,null,null,null,7,8,9,10,null,null,11,12]
 
 **Output:** [1,2,3,7,8,11,12,9,10,4,5,6]
 
-**Explanation:** The multilevel linked list in the input is shown. After flattening the multilevel linked list it becomes: ![](https://assets.leetcode.com/uploads/2021/11/09/flatten12.jpg)
+**Explanation:** The multilevel linked list in the input is shown. After flattening the multilevel linked list it becomes: ![](https://leetcode-images.github.io/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/flatten12.jpg) 
 
 **Example 2:**
 
-![](https://assets.leetcode.com/uploads/2021/11/09/flatten2.1jpg)
+![](https://leetcode-images.github.io/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/flatten21.jpg)
 
 **Input:** head = [1,2,null,3]
 
 **Output:** [1,3,2]
 
-**Explanation:** The multilevel linked list in the input is shown. After flattening the multilevel linked list it becomes: ![](https://assets.leetcode.com/uploads/2021/11/24/list.jpg)
+**Explanation:**
+
+    The multilevel linked list in the input is shown.
+    After flattening the multilevel linked list it becomes:
+
+![](https://leetcode-images.github.io/g0401_0500/s0430_flatten_a_multilevel_doubly_linked_list/list.jpg) 
 
 **Example 3:**
 
 **Input:** head = []
 
 **Output:** []
 
-**Explanation:** There could be empty list in the input.
+**Explanation:** There could be empty list in the input. 
 
 **Constraints:**
 
@@ -48,19 +53,29 @@ Return _the_ `head` _of the flattened list. The nodes in the list must have **al
 
 We use the multilevel linked list from **Example 1** above:
 
-1---2---3---4---5---6--NULL \| 7---8---9---10--NULL \| 11--12--NULL
+    1---2---3---4---5---6--NULL
+            |
+            7---8---9---10--NULL
+                |
+                11--12--NULL
 
 The serialization of each level is as follows:
 
-[1,2,3,4,5,6,null] [7,8,9,10,null] [11,12,null]
+    [1,2,3,4,5,6,null]
+    [7,8,9,10,null]
+    [11,12,null] 
 
 To serialize all levels together, we will add nulls in each level to signify no node connects to the upper node of the previous level. The serialization becomes:
 
-[1, 2, 3, 4, 5, 6, null] \| [null, null, 7, 8, 9, 10, null] \| [ null, 11, 12, null]
+    [1,    2,    3, 4, 5, 6, null]
+                 |
+    [null, null, 7,    8, 9, 10, null]
+                       |
+    [            null, 11, 12, null] 
 
 Merging the serialization of each level and removing trailing nulls we obtain:
 
-[1,2,3,4,5,6,null,null,null,7,8,9,10,null,null,11,12]
+    [1,2,3,4,5,6,null,null,null,7,8,9,10,null,null,11,12]
 
 ## Solution
 
diff --git a/src/main/kotlin/g2601_2700/s2619_array_prototype_last/readme.md b/src/main/kotlin/g2601_2700/s2619_array_prototype_last/readme.md
@@ -39,13 +39,13 @@ declare global {
 }
 
 Array.prototype.last = function () { //NOSONAR
-    return this.length !== 0 ? this[this.length - 1] : -1
+    return this.length !== 0 ? this[this.length - 1] : -1 //NOSONAR
 }
 
 /*
  * const arr = [1, 2, 3];
  * arr.last(); // 3
  */
 
-export {}
+export {} //NOSONAR
 ```
diff --git a/src/main/kotlin/g2601_2700/s2624_snail_traversal/readme.md b/src/main/kotlin/g2601_2700/s2624_snail_traversal/readme.md
@@ -73,5 +73,5 @@ Array.prototype.snail = function (rowsCount: number, colsCount: number): number[
  * arr.snail(1,4); // [[1,2,3,4]]
  */
 
-export {}
+export {} //NOSONAR
 ```
diff --git a/src/main/kotlin/g2601_2700/s2626_array_reduce_transformation/readme.md b/src/main/kotlin/g2601_2700/s2626_array_reduce_transformation/readme.md
@@ -70,7 +70,7 @@ type Fn = (accum: number, curr: number) => number
 
 function reduce(nums: number[], fn: Fn, init: number): number {
     let accumulator = init
-    nums.forEach((num) => {
+    nums.forEach((num) => { //NOSONAR
         accumulator = fn(accumulator, num)
     })
     return accumulator
diff --git a/src/main/kotlin/g2601_2700/s2630_memoize_ii/readme.md b/src/main/kotlin/g2601_2700/s2630_memoize_ii/readme.md
@@ -104,7 +104,7 @@ function memoize(fn: Fn): Fn {
 
         let value = fn(...args)
 
-        currentCache.set(args[args.length - 1], value)
+        currentCache.set(args[args.length - 1], value) //NOSONAR
         return value
     }
 }
diff --git a/src/main/kotlin/g2601_2700/s2631_group_by/readme.md b/src/main/kotlin/g2601_2700/s2631_group_by/readme.md
@@ -120,5 +120,5 @@ Array.prototype.groupBy = function <T>(fn: (item: T) => string) { //NOSONAR
  * [1,2,3].groupBy(String) // {"1":[1],"2":[2],"3":[3]}
  */
 
-export {}
+export {} //NOSONAR
 ```
diff --git a/src/main/kotlin/g2601_2700/s2693_call_function_with_custom_context/readme.md b/src/main/kotlin/g2601_2700/s2693_call_function_with_custom_context/readme.md
@@ -74,5 +74,5 @@ Function.prototype.callPolyfill = function (context, ...args): any { //NOSONAR
  * increment.callPolyfill({count: 1}); // 2
  */
 
-export {}
+export {} //NOSONAR
 ```
diff --git a/src/main/kotlin/g2601_2700/s2694_event_emitter/readme.md b/src/main/kotlin/g2601_2700/s2694_event_emitter/readme.md
@@ -88,18 +88,34 @@ type Subscription = {
 }
 
 class EventEmitter {
-    subs: Record<string, Callback[]> = {}
+    eventMap: Map<string, Set<Callback>>
+
+    constructor() {
+        this.eventMap = new Map()
+    }
 
     subscribe(eventName: string, callback: Callback): Subscription {
-        if (!this.subs[eventName]) this.subs[eventName] = []
-        const idx = this.subs[eventName].push(callback) - 1
+        if (this.eventMap.has(eventName)) {
+            const set = this.eventMap.get(eventName)!
+            set.add(callback)
+            this.eventMap.set(eventName, set)
+        } else {
+            const set = new Set<Callback>()
+            set.add(callback)
+            this.eventMap.set(eventName, set)
+        }
+
         return {
-            unsubscribe: () => this.subs[eventName].splice(idx, 1),
+            unsubscribe: () => {
+                this.eventMap.get(eventName).delete(callback)
+            },
         }
     }
 
     emit(eventName: string, args: any[] = []): any[] {
-        return this.subs[eventName]?.map((callback) => callback(...args)) || []
+        const res = []
+        this.eventMap.get(eventName)?.forEach((cb) => res.push(cb(...args))) //NOSONAR
+        return res
     }
 }
 
diff --git a/src/main/kotlin/g2701_2800/s2705_compact_object/readme.md b/src/main/kotlin/g2701_2800/s2705_compact_object/readme.md
@@ -46,7 +46,7 @@ type Obj = Record<any, any>
 function compactObject(obj: Obj): Obj {
     if (Array.isArray(obj)) {
         let retArr = []
-        obj.forEach((e, idx) => {
+        obj.forEach((e, idx) => { //NOSONAR
             if (e) {
                 retArr.push(compactObject(e))
             }
diff --git a/src/main/kotlin/g2701_2800/s2726_calculator_with_method_chaining/readme.md b/src/main/kotlin/g2701_2800/s2726_calculator_with_method_chaining/readme.md
@@ -76,7 +76,7 @@ class Calculator {
     }
 
     divide(value: number): Calculator { //NOSONAR
-        if (value === 0) throw Error('Division by zero is not allowed')
+        if (value === 0) throw new Error('Division by zero is not allowed')
         this.init /= value
         return this
     }
diff --git a/src/main/kotlin/g3001_3100/s3044_most_frequent_prime/readme.md b/src/main/kotlin/g3001_3100/s3044_most_frequent_prime/readme.md
@@ -17,7 +17,7 @@ Return _the most frequent prime number **greater** than_ `10` _out of all the nu
 
 **Example 1:**
 
- **![](https://assets.leetcode.com/uploads/2024/02/15/south)** 
+ **![](https://leetcode-images.github.io/g3001_3100/s3044_most_frequent_prime/south.png)** 
 
  **Input:** mat = \[\[1,1],[9,9],[1,1]]
 
diff --git a/src/main/kotlin/g3401_3500/s3426_manhattan_distances_of_all_arrangements_of_pieces/readme.md b/src/main/kotlin/g3401_3500/s3426_manhattan_distances_of_all_arrangements_of_pieces/readme.md
@@ -25,7 +25,7 @@ The Manhattan Distance between two cells <code>(x<sub>i</sub>, y<sub>i</sub>)</c
 
 The valid arrangements of pieces on the board are:
 
-![](https://assets.leetcode.com/uploads/2024/12/25/4040example1.drawio)![](https://assets.leetcode.com/uploads/2024/12/25/untitled-diagramdrawio.png)
+![](https://leetcode-images.github.io/g3401_3500/s3426_manhattan_distances_of_all_arrangements_of_pieces/untitled-diagramdrawio.png)
 
 *   In the first 4 arrangements, the Manhattan distance between the two pieces is 1.
 *   In the last 2 arrangements, the Manhattan distance between the two pieces is 2.
@@ -42,7 +42,7 @@ Thus, the total Manhattan distance across all valid arrangements is `1 + 1 + 1 +
 
 The valid arrangements of pieces on the board are:
 
-![](https://assets.leetcode.com/uploads/2024/12/25/4040example2drawio.png)
+![](https://leetcode-images.github.io/g3401_3500/s3426_manhattan_distances_of_all_arrangements_of_pieces/4040example2drawio.png)
 
 *   The first and last arrangements have a total Manhattan distance of `1 + 1 + 2 = 4`.
 *   The middle two arrangements have a total Manhattan distance of `1 + 2 + 3 = 6`.
diff --git a/src/main/kotlin/g3501_3600/s3519_count_numbers_with_non_decreasing_digits/readme.md b/src/main/kotlin/g3501_3600/s3519_count_numbers_with_non_decreasing_digits/readme.md
@@ -106,7 +106,7 @@ class Solution {
         while (i < n) {
             num[i] = arr[i++].code - '0'.code
         }
-        val temp: MutableList<Int?> = ArrayList<Int?>()
+        val temp: MutableList<Int> = ArrayList<Int>()
         var len = n
         while (len > 0) {
             var rem = 0
@@ -131,7 +131,7 @@ class Solution {
         var k = 0
         val size = temp.size
         while (k < size) {
-            res[k] = temp[size - 1 - k]!!
+            res[k] = temp[size - 1 - k]
             k++
         }
         return res
diff --git a/src/main/kotlin/g3701_3800/s3716_find_churn_risk_customers/readme.md b/src/main/kotlin/g3701_3800/s3716_find_churn_risk_customers/readme.md

Original file line number	Diff line number	Diff line change
`@@ -39,13 +39,13 @@ declare global {`
`39`	`39`	`}`
`40`	`40`
`41`	`41`	`Array.prototype.last = function () { //NOSONAR`
`42`		`- return this.length !== 0 ? this[this.length - 1] : -1`
	`42`	`+ return this.length !== 0 ? this[this.length - 1] : -1 //NOSONAR`
`43`	`43`	`}`
`44`	`44`
`45`	`45`	`/*`
`46`	`46`	`* const arr = [1, 2, 3];`
`47`	`47`	`* arr.last(); // 3`
`48`	`48`	`*/`
`49`	`49`
`50`		`-export {}`
	`50`	`+export {} //NOSONAR`
`51`	`51`	```
Original file line number	Diff line number	Diff line change
`@@ -104,7 +104,7 @@ function memoize(fn: Fn): Fn {`
`104`	`104`
`105`	`105`	`let value = fn(...args)`
`106`	`106`
`107`		`- currentCache.set(args[args.length - 1], value)`
	`107`	`+ currentCache.set(args[args.length - 1], value) //NOSONAR`
`108`	`108`	`return value`
`109`	`109`	`}`
`110`	`110`	`}`
Original file line number	Diff line number	Diff line change
`@@ -46,7 +46,7 @@ type Obj = Record<any, any>`
`46`	`46`	`function compactObject(obj: Obj): Obj {`
`47`	`47`	`if (Array.isArray(obj)) {`
`48`	`48`	`let retArr = []`
`49`		`- obj.forEach((e, idx) => {`
	`49`	`+ obj.forEach((e, idx) => { //NOSONAR`
`50`	`50`	`if (e) {`
`51`	`51`	`retArr.push(compactObject(e))`
`52`	`52`	`}`