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 `closedIslandCountGrid` method that counts islands fully surrounded by water.

Array Matrix Breadth First Search

Intermediate

Implement the `enclaveLandCellCount` method that counts land cells unable to reach the boundary.

Array Matrix Breadth First Search

Proficient

Implement the `longestIncreasingPathMatrix` method that returns the longest strictly increasing path length in a matrix.

Array String Hash Map Sliding Window

Guru

Implement the `shortestSubarrayAtLeastKLength` method that returns the shortest subarray length with sum at least k.

Array String Hash Map Sliding Window

Intermediate

Implement the `boundedMaximumSubarrayCount` method that counts subarrays whose maximum value stays within a given range.

Array String Hash Map Sliding Window

Intermediate

Implement the `longestSubstringAtMostKDistinctLength` method that returns the longest substring length with at most k distinct characters.

Array Sorting Binary Search

Proficient

Implement the `shipPackagesWithinDaysCapacity` method that returns the minimum ship capacity needed to deliver packages within given days.

Array Sorting Binary Search

Intermediate

Implement the `smallestDivisorUnderThreshold` method that finds the smallest divisor satisfying a threshold condition.

Array Sorting Binary Search

Intermediate

Implement the `kthMissingPositiveNumber` method that returns the kth missing positive integer from a sorted array.

Array Matrix Breadth First Search

Guru

Implement the `maximalRectangleArea` method that returns the largest rectangle of ones in a binary matrix.

Array Matrix Breadth First Search

Proficient

Implement the `surroundedRegionsSafeCount` method that counts cells not captured in a surrounded-regions board.

Array Matrix Breadth First Search

Intermediate

Implement the `nearestZeroDistanceSum` method that returns the sum of distances from every cell to its nearest zero.

Array Matrix Breadth First Search

Intermediate

Implement the `matrixBlockSumCenter` method that returns the block sum around the center using distance k.

Array Matrix Breadth First Search

Intermediate

Implement the `countSquareSubmatricesOnes` method that counts square submatrices that contain only 1 values.

Array Matrix Breadth First Search

Intermediate

Implement the `wordSearchMatrixExists` method that checks whether the word exists in the matrix path.

Array Matrix Breadth First Search

Intermediate

Implement the `minimumPathSumMatrix` method that returns the minimum path sum through the matrix.

Array Matrix Breadth First Search

Intermediate

Implement the `maximalSquareMatrixArea` method that returns the area of the largest square containing only 1 values.

Array Matrix Breadth First Search

Intermediate

Implement the `numberOfIslandsMatrix` method that counts islands in a binary matrix.

Array Matrix Breadth First Search

Intermediate

Implement the `searchSortedMatrix` method that checks whether the target exists in a sorted matrix.