Stack (52 completed) Back to top # Title Level Cats Solution Languages Date Complete 20 Valid Parentheses Easy B75, N150 solution java May 22, 2024 71 Simplify Path Medium solution py Jun 11, 2024 84 Largest Rectangle in Histogram Hard N150 solution py Jun 11, 2024 94 Binary Tree Inorder Traversal Easy solution java, py Jun 29, 2024 114 Flatten Binary Tree to Linked List Medium solution c, py Jun 11, 2024 143 Reorder List Medium B75, N150 solution java, py Jun 11, 2024 145 Binary Tree Postorder Traversal Easy Daily solution py Aug 25, 2024 150 Evaluate Reverse Polish Notation Medium N150 solution py Jun 11, 2024 155 Min Stack Medium N150 solution py Jun 16, 2024 173 Binary Search Tree Iterator Medium solution py Jun 26, 2024 224 Basic Calculator Hard solution py Jun 10, 2024 227 Basic Calculator II Medium solution py Jun 10, 2024 272 Closest Binary Search Tree Value II Hard solution py Jul 01, 2024 341 Flatten Nested List Iterator Medium solution java Jul 02, 2024 364 Nested List Weight Sum II Medium solution java, py Jul 02, 2024 394 Decode String Medium solution py Jun 15, 2024 426 Convert Binary Search Tree to Sorted Doubly Linked List Medium solution py Jun 12, 2024 503 Next Greater Element II Medium solution py Jul 05, 2024 590 N-ary Tree Postorder Traversal Easy Daily solution py Aug 26, 2024 636 Exclusive Time of Functions Medium solution py Aug 28, 2024 654 Maximum Binary Tree Medium solution py Jun 12, 2024 726 Number of Atoms Hard Daily solution py Jul 14, 2024 735 Asteroid Collision Medium solution py Jul 14, 2024 739 Daily Temperatures Medium N150 solution c, java, py Jun 13, 2024 853 Car Fleet Medium N150 solution py Jun 14, 2024 856 Score of Parentheses Medium solution py Jun 19, 2024 895 Maximum Frequency Stack Hard solution java, py Jul 11, 2024 921 Minimum Add to Make Parentheses Valid Medium Daily solution java, py Jun 12, 2024 946 Validate Stack Sequences Medium solution c, py Jun 12, 2024 1006 Clumsy Factorial Medium solution c, py Jun 12, 2024 1008 Construct Binary Search Tree from Preorder Traversal Medium solution c, cpp, java Jun 27, 2024 1019 Next Greater Node In Linked List Medium solution py Jun 22, 2024 1190 Reverse Substrings Between Each Pair of Parentheses Medium Daily solution py Jul 11, 2024 1209 Remove All Adjacent Duplicates in String II Medium solution py Jun 19, 2024 1249 Minimum Remove to Make Valid Parentheses Medium solution py Jun 10, 2024 1265 Print Immutable Linked List in Reverse Medium solution c, py Jun 06, 2024 1381 Design a Stack With Increment Operation Medium Daily solution py Jul 06, 2024 1472 Design Browser History Medium solution py Jul 06, 2024 1475 Final Prices With a Special Discount in a Shop Easy Daily solution py Dec 18, 2024 1598 Crawler Log Folder Easy Daily solution c, js Jul 10, 2024 1653 Minimum Deletions to Make String Balanced Medium Daily solution py Jul 30, 2024 1700 Number of Students Unable to Eat Lunch Easy solution py Jun 02, 2024 1717 Maximum Score From Removing Substrings Medium Daily solution py Jul 12, 2024 1762 Buildings With an Ocean View Medium solution py Jun 10, 2024 2130 Maximum Twin Sum of a Linked List Medium solution py Jun 21, 2024 2211 Count Collisions on a Road Medium solution py Jul 14, 2024 2390 Removing Stars From a String Medium solution java, py Jun 02, 2024 2487 Remove Nodes From Linked List Medium solution py Jun 12, 2024 2751 Robot Collisions Hard Daily solution py Jul 13, 2024 2816 Double a Number Represented as a Linked List Medium solution c Jul 04, 2024 3174 Biweekly Contest 132 - q1 - Clear Digits Easy Contest solution py Jul 07, 2024 3229 Weekly Contest 407 - q4 - Minimum Operations to Make Array Equal to Target Hard Contest solution py Jul 21, 2024