Code Challenges

Get better at coding with practice problems.

Coding Challenges

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

Stack Topological Sort Simulation

Intermediate

Implement the `minRemoveValidParentheses` method that removes the minimum invalid parentheses to make the text valid.

Stack Topological Sort Simulation

Proficient

Implement the `largestRectangleHistogram` method that returns the largest rectangle area possible in a histogram.

Stack Topological Sort Simulation

Intermediate

Implement the `dailyTemperaturesWait` method that returns how many days must be waited for a warmer temperature.

Stack Topological Sort Simulation

Learner

Implement the `nextGreaterElementArray` method that returns the next greater value for each array element.

Stack Topological Sort Simulation

Learner

Implement the `validParenthesesMixed` method that checks whether mixed parentheses are correctly balanced.

Math Decision Making Simulation

Learner

Implement the `detectCircularRouteSimple` method that checks whether the given movement sequence returns to the starting point.

Math Decision Making Simulation

Beginner

Implement the `validateBookingCapacity` method that checks whether a booking request fits within the available capacity.

Math Decision Making Simulation

Learner

Implement the `findWinnerTicTacToeRow` method that returns the winner found in any complete row of a tic-tac-toe board.

Math Decision Making Simulation

Learner

Implement the `simulateSimpleBrowserBack` method that simulates browser back navigation and returns the final page.

Math Decision Making Simulation

Intermediate

Implement the `checkBalancedScoreBrackets` method that checks whether scored bracket text remains balanced.

Math Decision Making Simulation

Intermediate

Implement the `validateStackPushPopSequence` method that checks whether a pop sequence is valid for the given push sequence.

Math Decision Making Simulation

Learner

Implement the `canAttendAllMeetings` method that checks whether a person can attend all given meetings.

Math Decision Making Simulation

Beginner

Implement the `meetingOverlapCheck` method that checks whether two time intervals overlap.

Math Decision Making Simulation

Intermediate

Implement the `rateLimiterAllowRequest` method that checks whether a request is allowed under a simple rate limit.

Math Decision Making Simulation

Learner

Implement the `validateIpSegmentSimple` method that checks whether a text segment is valid for an IP address part.

Decision Making Stack Simulation

Learner

Implement the `isValidBracketPairString` method that checks whether a bracket string has properly matched and ordered brackets.

Math Number Theory Simulation

Intermediate

Implement the `isHappyNumber` method that checks whether repeatedly summing the squares of digits reaches 1.

String Manipulation String Stack Simulation

Learner

Implement the `removeAdjacentDuplicates` method that removes adjacent duplicate characters using stack-style processing.