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Stack

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53 entries

53 entries tagged as Stack.

24.05.2026

hard

1340. Jump Game V

Kotlin Rust

Max visited by jumping down in distance d

Dynamic Programming Graph Stack

stack array dynamic programming depth-first search monotonic stack monotonic stack for range queries

Full post LeetCode Kotlin Rust YouTube Telegram

01.04.2026

hard

2751. Robot Collisions

Kotlin Rust

Collide LR robots

Stack Sorting Simulation

stack array sorting in-place stack simulation collision simulation simulation

Full post LeetCode YouTube Telegram

11.01.2026

hard

85. Maximal Rectangle

Kotlin Rust

Max all-1 rectangle in 2D matrix stack

Monotonic Stack Stack Array

stack matrix monotonic stack sentinel value to simplify iteration height accumulation per column arrays

Full post LeetCode Kotlin Rust YouTube Telegram

10.11.2025

medium

3542. Minimum Operations to Convert All Elements to Zero

Kotlin Rust

Min ops to zeros by making min of subarrays 0 stack

Monotonic Stack Stack

input array as stack monotonic stack greedy strategy based on monotonic stack maintenance array manipulation

Full post LeetCode Kotlin Rust YouTube Telegram

23.07.2025

medium

1717. Maximum Score From Removing Substrings

Kotlin Rust

Max removals ab=x, ba=y

Stack

Full post LeetCode Kotlin Rust YouTube Telegram

06.06.2025

medium

2434. Using a Robot to Print the Lexicographically Smallest String

Kotlin Rust

Smallest string by writing to stack

String Stack Simulation

stack array list greedy monotonic-stack strings

Full post LeetCode Kotlin Rust YouTube Telegram

29.03.2025

hard

2818. Apply Operations to Maximize Score

Kotlin Rust

Multiply k numbers with max prime factor count stack

Monotonic Stack Stack Math

nums sort_by_value left_and_right_pointers modular_exponentiation prime_factor_count_calculation subarray_range_determination

Full post LeetCode Kotlin Rust YouTube Telegram

23.02.2025

medium

889. Construct Binary Tree from Preorder and Postorder Traversal

Kotlin Rust

Tree from preorder & postorder

Stack Tree

Full post LeetCode Kotlin Rust YouTube Telegram

22.02.2025

hard

1028. Recover a Tree From Preorder Traversal

Kotlin Rust

Recover binary tree from depth-dashes string

Stack Tree String

tree recursion stack

Full post LeetCode Kotlin Rust YouTube Telegram

27.12.2024

medium

1014. Best Sightseeing Pair

Kotlin Rust

Max (a[i] + a[j] + i - j), i > j

Monotonic Stack Stack Sorting

Full post LeetCode Kotlin Rust YouTube Telegram

22.12.2024

hard

2940. Find Building Where Alice and Bob Can Meet

Kotlin Rust

Common indices t, h[t] > h[a], h[t] > h[b] for queries q[][a,b] stack

Binary Search Monotonic Stack Stack

monotonic_stack binary_search monotonic_stack_for_range_queries binary_search_on_monotonic_stack range_queries arrays

Full post LeetCode Kotlin Rust YouTube Telegram

18.12.2024

easy

1475. Final Prices With a Special Discount in a Shop

Kotlin Rust

Subtract next smaller value stack

Monotonic Stack Stack Simulation

monotonic_stack stack arrays strings

Full post LeetCode Kotlin Rust YouTube Telegram

13.12.2024

medium

2593. Find Score of an Array After Marking All Elements

Kotlin Rust

Sum of minimums in order excluding siblings stack

Monotonic Stack Stack Sorting

Stack Vector Monotonic Stack Sorting Alternating Sums Arrays

Full post LeetCode Kotlin Rust YouTube Telegram

27.10.2024

medium

1277. Count Square Submatrices with All Ones

Kotlin Rust

Count 1-filled squares in 2D matrix programming

Dynamic Programming Monotonic Stack Stack

matrix dynamic_programming array grid

Full post LeetCode Kotlin Rust YouTube

20.10.2024

hard

1106. Parsing A Boolean Expression

Kotlin Rust

before evaluation, index i should point at the first token of the subproblem

Stack

stack recursion polish-notation strings

Full post LeetCode Kotlin Rust YouTube Telegram

10.10.2024

medium

962. Maximum Width Ramp

Kotlin Rust

Max j-i between a[i] <= a[j] in an array stack

Monotonic Stack Stack Sorting

monotonic_stack array sorting algorithm

Full post LeetCode Kotlin Rust YouTube Telegram

09.10.2024

medium

921. Minimum Add to Make Parentheses Valid

Kotlin Rust

Minimum inserts to balance brackets

Stack Hash Map

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08.10.2024

medium

1963. Minimum Number of Swaps to Make the String Balanced

Kotlin Rust

Min swaps to balance brackets pointers

Stack Two Pointers String

Two pointers approach for identifying misplaced brackets. Implicit use of a stack concept via balance tracking to manage bracket nesting. String manipulation and bracket balancing. Linear scan over the input string.

Full post LeetCode Kotlin Rust YouTube Telegram

07.10.2024

easy

2696. Minimum String Length After Removing Substrings

Kotlin Rust

Remove 'AB' and 'CD' from the string

Stack String

stack stack-based-removal strings

Full post LeetCode Kotlin Rust YouTube Telegram

30.09.2024

medium

1381. Design a Stack With Increment Operation

Kotlin Rust

Stack with range increment operation

Stack Array

array hash-map dynamic-programming space-optimization prefix-sum data-structures

Full post LeetCode Kotlin Rust YouTube Telegram

14.07.2024

hard

726. Number of Atoms

Kotlin Rust

Simplify chemical formula parenthesis

Stack

hash-map stack recursion depth-first-search reverse-traversal strings

Full post LeetCode Kotlin Rust YouTube Telegram

13.07.2024

hard

2751. Robot Collisions

Kotlin Rust

D dimensional robots fight

Stack Sorting Simulation

stack array sorting stack_matching sorting_by_position simulation

Full post LeetCode Kotlin Rust YouTube Telegram

12.07.2024

medium

1717. Maximum Score From Removing Substrings

Kotlin Rust

Max score removing from s, x for ab, y for ba

Greedy Stack

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12.05.2024

easy

2373. Largest Local Values in a Matrix

Kotlin Rust

Max pooling by 3x3 matrix

Monotonic Stack Stack Array

matrix none local-window-max

Full post LeetCode Kotlin Rust YouTube Telegram

06.05.2024

medium

2487. Remove Nodes From Linked List

Kotlin Rust

Make a Linked List non-increasing list

Monotonic Stack Stack Linked List

linked-list two-pointers reverse-linked-list

Full post LeetCode Kotlin Rust YouTube Telegram

13.04.2024

hard

85. Maximal Rectangle

Kotlin Rust

Max 1-only area in a 0-1 matrix

Stack Math Array

stack monotonic-stack array matrix

Full post LeetCode Kotlin Rust YouTube Telegram

12.04.2024

hard

42. Trapping Rain Water

Kotlin Rust

Trap the water in area between vertical walls

Stack

Stack Array Decreasing Stack Area Calculation Arrays Geometry

Full post LeetCode Kotlin Rust YouTube

11.04.2024

medium

402. Remove K Digits

Kotlin Rust

Minimum number after removing k digits

Stack

stack string greedy increasing_stack strings arrays

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06.04.2024

medium

1249. Minimum Remove to Make Valid Parentheses

Kotlin Rust

Remove minimum to make parenthesis valid

Stack

implicit_stack result_array single_pass_iteration prefix_balance_tracking open_count_management post_processing_cleanup

Full post LeetCode Kotlin Rust YouTube Telegram

05.04.2024

easy

1544. Make The String Great

Kotlin Rust

Remove lowercase-uppercase pairs

Stack String

stringbuilder vector stack stack_processing case_insensitivity strings

Full post LeetCode Kotlin Rust YouTube Telegram

31.01.2024

medium

739. Daily Temperatures

Kotlin Rust

Array of distances to the next largest.

Monotonic Stack Stack Array

Stack Array Monotonic Stack Arrays

Full post LeetCode Kotlin Rust YouTube Telegram

30.01.2024

medium

150. Evaluate Reverse Polish Notation

Kotlin Rust

Solve Reverse Polish Notation.

Stack

Stack Dynamic Programming Stack-based Evaluation Arithmetic

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20.01.2024

medium

907. Sum of Subarray Minimums

Kotlin Rust

Sum of minimums of all array ranges.

Stack Array

stack array folding increasing_stack arrays math

Full post LeetCode Kotlin Rust YouTube Telegram

20.10.2023

medium

341. Flatten Nested List Iterator

Kotlin

Implement graph iterator

Graph Stack

Stack List Stack usage Lists Iteration

Full post LeetCode Kotlin Telegram

19.10.2023

medium

844. Backspace String Compare

Kotlin

Remove all of the backspaced chars before comparing

Stack String

stack two-pointers strings

Full post LeetCode Kotlin Telegram

30.09.2023

medium

456. 132 Pattern

Kotlin

132 pattern in array

Monotonic Stack Stack Array

Stack Array Linear Scan Monotonic Stack Arrays Pattern Matching

Full post LeetCode Kotlin Telegram

28.08.2023

easy

225. Implement Stack using Queues

Kotlin

Create a Stack using Queue's push/pop methods.

Stack Queue

queue linked-list rotation data-structures queues

Full post LeetCode Kotlin Telegram

20.07.2023

medium

735. Asteroid Collision

Kotlin

Result after asteroids collide left-right exploding by size: 15 5 -15 -5 5 -> -15 -5 5

Stack

Stack Stack-based collision resolution Popping elements based on collision rules Arrays

Full post LeetCode Kotlin Telegram

17.07.2023

medium

445. Add Two Numbers II

Kotlin

Linked List of sum of two Linked Lists numbers, 9->9 + 1 = 1->0->0

Stack Linked List

ListNode Stack Reverse operation List Reversal Digit by Digit Sum

Full post LeetCode Kotlin Telegram

17.05.2023

medium

2130. Maximum Twin Sum of a Linked List

Kotlin

Max sum of head-tail twin ListNodes: a-b-c-d -> max(a+d, b+c)

Stack Linked List

Stack Linked List Two Pointers Stack Usage

Full post LeetCode Kotlin Telegram

13.04.2023

medium

946. Validate Stack Sequences

Kotlin

use one iteration and a second pointer for pop

Stack Simulation

stack simulation stack_simulation arrays

Full post LeetCode Kotlin Telegram

12.04.2023

medium

71. Simplify Path

Kotlin

split the string by /

Stack Simulation String

Stack Stack Simulation Strings

Full post LeetCode Kotlin Telegram

11.04.2023

medium

2390. Removing Stars From a String

Kotlin

we can use a Stack, or just StringBuilder

Stack String

StringBuilder Iteration String building manipulation Strings

Full post LeetCode Kotlin Telegram

10.04.2023

medium

20. Valid Parentheses

Kotlin

use HashMap to check matching bracket.

Stack Hash Map String

Stack HashMap Linear Scan Stack-based Stack-matching Strings

Full post LeetCode Kotlin Telegram

13.03.2023

easy

101. Symmetric Tree

Kotlin

Recursive: just write helper function.

Graph Tree Stack

ArrayDeque Stack Recursion Breadth-First Search Stack usage for level-order traversal simulation Recursive comparison of mirrored subtrees

Full post LeetCode Kotlin Telegram

8.02.2023

medium

45. Jump Game II

Kotlin

use stack to store jumps

Stack Greedy

Stack Greedy Stack Optimization Array Jump Game

Full post LeetCode Kotlin Telegram

10.01.2023

easy

100. Same Tree

Kotlin

fun isSameTree(p: TreeNode?, q: TreeNode?): Boolean = p == null && q == null ||

Tree Stack

TreeNode recursive traversal recursive comparison of tree structures

Full post LeetCode Kotlin Telegram

18.12.2022

medium

739. Daily Temperatures

Kotlin

fun dailyTemperatures(temperatures: IntArray): IntArray {

Stack

Stack Monotonic Stack Reverse Iteration Arrays

Full post LeetCode Kotlin Telegram

17.12.2022

medium

150. Evaluate Reverse Polish Notation

Kotlin

fun evalRPN(tokens: Array): Int = with(Stack()) {

Stack String Array

Stack Stack-based evaluation Arithmetic

Full post LeetCode Kotlin Telegram

16.12.2022

easy

232. Implement Queue using Stacks

Kotlin

class MyQueue() {

Stack Queue

Stack Queue reversal arrays

Full post LeetCode Kotlin Telegram

13.11.2022

medium

Reverse Words In A String

Kotlin

A simple trick: reverse all the string, then reverse each word.

Stack String

Stack Strings

Full post LeetCode

10.11.2022

easy

Remove All Adjacent Duplicates In String

Just scan symbols one by one and remove duplicates from the end.

Stack String

stack string stack-based stack-for-removal strings

Full post LeetCode

9.11.2022

medium

Online Stock Span

Kotlin

So, we need to keep increasing sequence of numbers, increasing/decreasing stack will help.

Stack

stack pair monotonic-stack array

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