Stack problems

123 Stack problems on CampusCode, in order. Open any for its full statement, examples and constraints.

• 564. Check Balanced Parentheses Easy
• 565. Reverse a String Using Stack Easy
• 566. Evaluate Postfix Expression Easy
• 567. Convert Infix to Postfix Easy
• 568. Reverse a Stack Using Recursion Easy
• 569. Sort a Stack Using Recursion Easy
• 570. Find Middle Element of Stack Easy
• 571. Delete Middle Element of Stack Easy
• 572. Check if Stack is Palindrome Easy
• 573. Count Occurrences of Element in Stack Easy
• 574. Reverse a Number Using Stack Easy
• 575. Valid Parentheses (Multiple Types) Easy
• 576. Remove All Adjacent Duplicates in String Easy
• 577. Make String Great Easy
• 578. Baseball Game Score Easy
• 579. Reverse First K Elements of Queue Easy
• 580. Interleave First Half with Second Half Easy
• 581. Generate Binary Numbers from 1 to N Easy
• 582. BFS Level Order Traversal Using Queue Easy
• 583. Check if Queue is Palindrome Easy
• 584. Sliding Window Maximum Easy
• 585. Students Unable to Eat Lunch Easy
• 586. Time Needed to Buy Tickets Easy
• 587. First Non-Repeating Character in Stream Easy
• 588. Number of Recent Calls Easy
• 589. Next Greater Element Easy
• 590. Next Smaller Element Easy
• 591. Previous Greater Element Easy
• 592. Previous Smaller Element Easy
• 593. Stock Span Problem Easy
• 594. Next Greater Element I Easy
• 595. Next Greater Element in Circular Array Easy
• 596. Evaluate Prefix Expression Easy
• 597. Balanced Brackets with Wildcard Easy
• 598. Maximum Nesting Depth of Parentheses Easy
• 599. Task Scheduler — Simple Version Easy
• 600. Convert Decimal to Binary Using Stack Easy
• 601. Delete Consecutive Same Words Easy
• 602. Count Pairs of Matching Parentheses Easy
• 603. Simplify Unix Directory Path Easy
• 604. Score of Parentheses Easy
• 605. Remove K Digits to Get Smallest Number Easy
• 606. Crawler Log Folder Easy
• 607. Rotting Oranges — BFS via Queue Easy
• 608. Next Greater Element II (Circular Array) Medium
• 609. Daily Temperatures Medium
• 610. Largest Rectangle in Histogram Medium
• 611. Maximal Rectangle in Binary Matrix Medium
• 612. Decode String (Nested Brackets) Medium
• 613. Asteroid Collision Medium
• 614. 132 Pattern Medium
• 615. Remove Duplicate Letters Medium
• 616. Online Stock Span Medium
• 617. Max Width Ramp Medium
• 618. Exclusive Time of Functions Medium
• 619. Sum of Subarray Minimums Medium
• 620. Sum of Subarray Maximums Medium
• 621. Sliding Window Maximum (Monotonic Deque) Medium
• 622. Task Scheduler (Greedy + Queue) Medium
• 623. Jump Game VI (DP + Monotonic Deque) Medium
• 624. Maximum of Minimum for Every Window Size Medium
• 625. Dota2 Senate Medium
• 626. Reveal Cards in Increasing Order Medium
• 627. Design Snake Game Medium
• 628. Open the Lock (BFS + Queue) Medium
• 629. Car Fleet Medium
• 630. Remove Nodes From Linked List Medium
• 631. Number of Visible People in Queue Medium
• 632. Build an Array With Stack Operations Medium
• 633. Validate Stack Sequences Medium
• 634. Count Collisions on a Road Medium
• 635. Minimum Add to Make Parentheses Valid Medium
• 636. Minimum Insertions to Balance Parentheses Medium
• 637. Longest Valid Parentheses Medium
• 638. Number of Atoms Medium
• 639. Walls and Gates Medium
• 640. Shortest Path in Binary Matrix Medium
• 641. Perfect Squares Medium
• 642. As Far from Land as Possible Medium
• 643. Map of Highest Peak Medium
• 644. Constrained Subsequence Sum Medium
• 645. Minimum Cost Tree From Leaf Values Medium
• 646. Buildings With an Ocean View Medium
• 647. Snakes and Ladders Medium
• 648. Removing Stars From a String Medium
• 649. Count of Students Unable to Eat Lunch Medium
• 650. Minimum Number of Flips to Convert Binary Matrix to Zero Medium
• 651. Check If Word Is Valid After Substitutions Medium
• 652. Implement a Basic Calculator II Medium
• 653. Trapping Rain Water Hard
• 654. Largest Rectangle in Histogram (Optimal) Hard
• 655. Maximal Rectangle Hard
• 656. Basic Calculator I Hard
• 657. Basic Calculator III Hard
• 658. Longest Valid Parentheses (O(1) Space) Hard
• 659. Remove Invalid Parentheses Hard
• 660. Max Width Ramp (Optimal) Hard
• 661. Count Submatrices With All Ones Hard
• 662. Sum of Total Strength of Wizards Hard
• 663. Number of Visible Pairs in a Queue Hard
• 664. Maximum Score From Multiplication Operations Hard
• 665. Minimum Swaps to Make String Balanced Hard
• 666. Shortest Unsorted Continuous Subarray Hard
• 667. Find the Most Competitive Subsequence Hard
• 668. Sliding Window Minimum and Maximum Together Hard
• 669. Max Sum of Rectangle No Larger Than K Hard
• 670. Minimum Cost Jump Game (Monotonic Queue DP) Hard
• 671. Minimum Cost to Cut a Stick Hard
• 672. Shortest Path in a Grid with Obstacles Elimination Hard
• 673. Sliding Puzzle — Minimum Moves Hard
• 674. Cut Off Trees for Golf Event Hard
• 675. Minimum Genetic Mutation Hard
• 676. Word Ladder — Shortest Transformation Hard
• 677. Maximal Score After Applying K Operations Hard
• 678. Count Subarrays With Score Less Than K Hard
• 679. Maximum Robots Within Budget Hard
• 680. Sum of Subarray Ranges Hard
• 681. Steps to Make Array Non-decreasing Hard
• 682. Maximum Points in an Archery Competition Hard
• 683. Minimum Cost to Reach Destination in Time Hard
• 684. Maximum Binary Tree (Monotonic Stack Build) Hard
• 685. Bus Routes Hard
• 686. Flatten Binary Tree to Linked List Hard