Code Challenges

Get better at coding with practice problems.

Coding Challenges

Select a problem, write code, run test cases, and submit your solution.

Recursion Backtracking Combinatorics

Intermediate

Implement the `restoreIpAddressesCount` method that counts valid IP addresses that can be restored from the digits.

Recursion Backtracking Combinatorics

Proficient

Implement the `palindromePartitionCount` method that counts palindrome partitions possible for the text.

Recursion Backtracking Combinatorics

Intermediate

Implement the `letterCombinationsPhoneCount` method that counts letter combinations generated from phone digits.

Recursion Backtracking Combinatorics

Intermediate

Implement the `sudokuValidPlacementCount` method that counts how many filled Sudoku cells are validly placed.

Recursion Backtracking Combinatorics

Guru

Implement the `nQueensSolutionCount` method that counts valid ways to place n queens on the board.

Recursion Backtracking Combinatorics

Intermediate

Implement the `wordSearchGridExists` method that checks whether a word can be formed in the grid by adjacent cells.

Recursion Backtracking Combinatorics

Learner

Implement the `subsetsCountDistinct` method that counts distinct subsets that can be formed from the values.

Recursion Backtracking Combinatorics

Intermediate

Implement the `permutationsCountDistinct` method that counts distinct permutations of the given values.

Recursion Backtracking Combinatorics

Intermediate

Implement the `combinationSumCount` method that counts combinations that can sum to the target.

Recursion Backtracking Combinatorics

Intermediate

Implement the `generateParenthesesCountImportant` method that counts valid parentheses combinations for n pairs.

Dynamic Programming Recursion Memoization Tabulation

Learner

Implement the `climbStairsWays` method that returns the number of distinct ways to climb n stairs.

String Dynamic Programming Recursion

Guru

Implement the method `editDistance` that returns the minimum number of edits needed to convert one string into another.