Code Challenges

Get better at coding with practice problems.

Coding Challenges

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

Array Matrix Breadth First Search

Intermediate

Implement the `rotateImageClockwise` method that returns the matrix after rotating it 90 degrees clockwise.

Array Matrix Breadth First Search

Intermediate

Implement the `spiralOrderTraversalLength` method that returns the number of elements visited in spiral order.

Array Matrix Breadth First Search

Intermediate

Implement the `setMatrixZeroesCount` method that counts cells affected after applying matrix zeroing rules.

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.

Math Bit Manipulation

Learner

Implement the `subsetsCountByBitmask` method that returns how many subsets can be formed using bitmasking.

Math Bit Manipulation

Proficient

Implement the `maximumXorPairSimple` method that returns the maximum XOR value obtainable from any pair.

Math Bit Manipulation

Learner

Implement the `hammingDistanceValues` method that returns the number of bit positions where two integers differ.

Math Bit Manipulation

Learner

Implement the `powerOfFourCheck` method that checks whether a number is a power of four.

Math Bit Manipulation

Learner

Implement the `missingNumberXorImportant` method that finds the missing number using XOR logic.

Math Bit Manipulation

Intermediate

Implement the `bitwiseAndRange` method that returns the bitwise AND of all numbers in the given range.