Pattern

Backtracking

A compact view of archive entries grouped by recurring technique.

Back to library Library RSS

38 entries

38 entries tagged as Backtracking.

07.10.2026

hard

301. Remove Invalid Parentheses

Kotlin Rust

Min removal to make balanced strings

Graph Backtracking String

Full post LeetCode Kotlin Rust YouTube Telegram

17.02.2026

easy

401. Binary Watch

Kotlin Rust

All times with count bits set

Backtracking Bit Manipulation

bitmask bit manipulation backtracking brute force bit counting next smallest bitmask generation

Full post LeetCode Kotlin Rust YouTube Telegram

29.12.2025

medium

756. Pyramid Transition Matrix

Kotlin Rust

Can build a pyramid from transitions?

Backtracking Graph Array

hash set bitmask array depth-first search backtracking bitmask optimization

Full post LeetCode Kotlin Rust YouTube Telegram

31.08.2025

hard

37. Sudoku Solver

Kotlin

Solve sudoku

Backtracking Graph

rows s depth-first-search brute-force search with pruning using bitmasks for constraint checking grid manipulation

Full post LeetCode Kotlin YouTube Telegram

18.08.2025

hard

679. 24 Game

Kotlin

Can a,b,c,d = 24 with ops /+-()

Backtracking Math

list array backtracking recursion dfs math_operations

Full post LeetCode Kotlin YouTube Telegram

28.07.2025

medium

2044. Count Number of Maximum Bitwise-OR Subsets

Kotlin Rust

Subsequencies with max OR

Bit Manipulation Backtracking Dynamic Programming

n m brute-force dp iterating_subsets traverse_all_subsequences

Full post LeetCode Kotlin Rust YouTube Telegram

27.06.2025

hard

2014. Longest Subsequence Repeated k Times

Kotlin Rust

Longest k-repeating subsequence

Backtracking Graph

implicit explicit explicit explicit explicit

Full post LeetCode Kotlin Rust YouTube Telegram

12.05.2025

easy

2094. Finding 3-Digit Even Numbers

Kotlin Rust

Triple digit even numbers from digits

Backtracking Hash Map

array list backtracking depth-first-search brute-force combinatorics

Full post LeetCode Kotlin Rust YouTube Telegram

05.04.2025

easy

1863. Sum of All Subset XOR Totals

Kotlin Rust

Sum of all subsets xors

Bit Manipulation Math Backtracking

input array and masks intermediate XOR sums iterating all subsets via bitmasks recursive approach for subset XOR sums using bitmasks to represent subsets exploiting the properties of XOR for subset sums

Full post LeetCode Kotlin Rust YouTube Telegram

20.02.2025

medium

1980. Find Unique Binary String

Kotlin Rust

Binary number not in a set

Backtracking Graph Sorting

n set backtracking sorting cantors_diagonal_argument strings

Full post LeetCode Kotlin Rust YouTube Telegram

19.02.2025

medium

1415. The k-th Lexicographical String of All Happy Strings of Length n

Kotlin Rust

kth string of abc permutations

Backtracking Graph Math

backtracking depth-first-search brute-force combinatorial-counting strings permutations

Full post LeetCode Kotlin Rust YouTube Telegram

18.02.2025

medium

2375. Construct Smallest Number From DI String

Kotlin Rust

Smallest number from 1..9 and Inc-Dec pattern

Backtracking Greedy String

backtracking greedy strings

Full post LeetCode Kotlin Rust YouTube Telegram

17.02.2025

medium

1079. Letter Tile Possibilities

Kotlin Rust

Count uniq sequences from letters

Backtracking

set vector backtracking memoization frequency_counting strings

Full post LeetCode Kotlin Rust YouTube Telegram

16.02.2025

medium

1718. Construct the Lexicographically Largest Valid Sequence

Kotlin Rust

Construct array x = 1..n, a[i] = x, a[i + x] = x

Backtracking Array

x dfs depth-first search sequence construction array manipulation

Full post LeetCode Kotlin Rust YouTube Telegram

15.02.2025

medium

2698. Find the Punishment Number of an Integer

Kotlin Rust

Sum x^2 if it's string partition sum = x

Backtracking String

backtracking recursion brute-force division_by_powers mathematics strings

Full post LeetCode Kotlin Rust YouTube Telegram

30.11.2024

hard

2097. Valid Arrangement of Pairs

Kotlin Rust

Hierholzer algorithm

Graph Backtracking

m stack hierholzer_algorithm hierholzer_algorithm greedy_traversal directed_graph

Full post LeetCode Kotlin Rust YouTube Telegram

21.10.2024

medium

1593. Split a String Into the Max Number of Unique Substrings

Kotlin Rust

Max count of unique split parts

Backtracking String

HashSet Backtracking Depth-First Search Strings

Full post LeetCode Kotlin Rust YouTube Telegram

18.10.2024

medium

2044. Count Number of Maximum Bitwise-OR Subsets

Kotlin Rust

Count subsequences with max bitwise or

Backtracking Bit Manipulation

none backtracking depth-first-search subsequences

Full post LeetCode Kotlin Rust YouTube Telegram

16.10.2024

medium

1405. Longest Happy String

Kotlin Rust

Longest string of a, b, c not repeating 3 times

Greedy Graph Backtracking

possible longest_diverse_string always_take_most_abundant maintain_possible_counts string_construction string_arrangement

Full post LeetCode Kotlin Rust YouTube Telegram

21.09.2024

medium

386. Lexicographical Numbers

Kotlin Rust

Lexicographical ordered numbers 1..n

Graph Trie Backtracking

Trie List DFS DFS Traversal Trie Construction Strings

Full post LeetCode Kotlin Rust YouTube Telegram

18.09.2024

medium

179. Largest Number

Kotlin Rust

Concatenate nums to largest number

Math Backtracking Sorting

sorting custom comparator strings arrays

Full post LeetCode Kotlin Rust YouTube Telegram

13.08.2024

medium

40. Combination Sum II

Kotlin Rust

Unique target sum subsequences

Backtracking Simulation

candidates result dfs sort candidates to handle duplicates and prune search space breaking early when sum exceeds target skipping identical elements in the loop to avoid duplicate combinations

Full post LeetCode Kotlin Rust YouTube Telegram

11.08.2024

hard

1568. Minimum Number of Days to Disconnect Island

Kotlin Rust

Min changes 1 to 0 to disconnect islands

Union Find Backtracking Simulation

Union-Find Hash-Map Depth-First Search Backtracking Connected Components Grid

Full post LeetCode Kotlin Rust YouTube Telegram

20.07.2024

medium

1605. Find Valid Matrix Given Row and Column Sums

Kotlin Rust

Matrix from rows and cols sums

Backtracking Array

matrix greedy matrix

Full post LeetCode Kotlin Rust YouTube Telegram

24.05.2024

hard

1255. Maximum Score Words Formed by Letters

Kotlin Rust

Max score of words subset from letters

Backtracking Graph

f dfs precompute_counts word_formation subset_sum

Full post LeetCode Kotlin Rust YouTube Telegram

23.05.2024

medium

2597. The Number of Beautiful Subsets

Kotlin Rust

Count subsets without k difference in them

Graph Backtracking Dynamic Programming

list backtracking depth-first-search sorting combinatorics arrays

Full post LeetCode Kotlin Rust YouTube Telegram

22.05.2024

medium

131. Palindrome Partitioning

Kotlin Rust

All palindrome partitions programming

Graph Dynamic Programming Backtracking

none backtracking dynamic_programming substring_check strings

Full post LeetCode Kotlin Rust YouTube Telegram

21.05.2024

medium

78. Subsets

Kotlin Rust

All subsets

Backtracking Dynamic Programming Graph

backtracking dynamic-programming dfs combinatorics arrays

Full post LeetCode Kotlin Rust YouTube Telegram

20.05.2024

easy

1863. Sum of All Subset XOR Totals

Kotlin Rust

Sum of subsets xors

Graph Backtracking Bit Manipulation

nums dfs brute-force dfs subsets

Full post LeetCode Kotlin Rust YouTube Telegram

14.05.2024

medium

1219. Path with Maximum Gold

Kotlin Rust

Max one-way path in matrix

Graph Backtracking Array

grid depth-first search backtracking grid

Full post LeetCode Kotlin Rust YouTube Telegram

10.05.2024

medium

786. K-th Smallest Prime Fraction

Kotlin Rust

kth arr[i]/arr[j], i < j, arr[i] < arr[j] search

Heap Backtracking Binary Search

heap arrays heap binary_search two_pointers arrays

Full post LeetCode Kotlin Rust YouTube Telegram

25.04.2024

medium

2370. Longest Ideal Subsequence

Kotlin Rust

Max length of less than k adjacent subsequence programming

Dynamic Programming Backtracking

dp_array implicit_memoization dp iterative_update state_memoization range_optimization

Full post LeetCode Kotlin Rust YouTube Telegram

14.09.2023

hard

332. Reconstruct Itinerary

Kotlin

Smallest lexical order path using all the tickets

Graph Backtracking

fromTo path usedTickets depth-first search sorting edges by destination string recursive path exploration with backtracking

Full post LeetCode Kotlin Telegram

05.08.2023

medium

95. Unique Binary Search Trees II

Kotlin

All possible Binary Search Trees for 1..n numbers

Tree Backtracking Binary Search

stack tree backtracking dfs bitmask hash_set

Full post LeetCode Kotlin Telegram

02.08.2023

medium

46. Permutations

Kotlin

List of all numbers permutations

Graph Backtracking Simulation

bitmask backtracking dfs permutations arrays

Full post LeetCode Kotlin Telegram

15.07.2023

hard

1751. Maximum Number of Events That Can Be Attended II

Kotlin

Max sum of at most k values from non-intersecting array of (from, to, value) items

Backtracking Queue Heap

events cache dfs search_next sort_by_start_time dfs_with_memoization

Full post LeetCode Kotlin Telegram

1.07.2023

medium

2305. Fair Distribution of Cookies

Kotlin

Min of the max distributing n cookies to k children

Graph Backtracking

backtracking depth-first search combinatorics

Full post LeetCode Kotlin Telegram

27.06.2023

medium

373. Find K Pairs with Smallest Sums

Kotlin

List of increasing sum pairs a[i], b[j] from two sorted lists a, b

Graph Backtracking Two Pointers

heap set dijkstra visited-set pairs sorting

Full post LeetCode Kotlin Telegram