Leetcode

1361. Validate Binary Tree Nodes

Question

Solution

• BFS (Breadth First Search); Pre-order Traversal, In-order Traversal, Post-order Traversal; Queue
• DFS (Depth First Search); Level-order Traversal; Stack
• mutable, immutable
• push, pop
• https://stackoverflow.com/questions/5250733/what-are-the-advantages-and-disadvantages-of-recursion
• https://stackoverflow.com/questions/575196/why-can-a-function-modify-some-arguments-as-perceived-by-the-caller-but-not-oth

342. Power of Four

Question

Solution

• quotient
• remainder

501. Find Mode in Binary Search Tree

Question

Solution

• BST (Binary Search Tree) in-order travesal can get the sorted list.
• Morris Traversal

1845. Seat Reservation Manager

Question

Solution

• Min-heap/Max-heap
• Python has the heapq for building Min-heap

Bit Manipulation

Bit Manipulation