Robina Li

Given an integer array nums, return true if any value appears at least twice, and false if every element is distinct.

Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values equals targetSum. Each path should be returned as...

Given the root of a binary tree, return the inorder traversal of its nodes’ values. Inorder visits: left → root → right.

Given the root of a binary tree, return the length of the diameter of the tree. The diameter is the length of the longest path between any two nodes (measured...

Given the root of a binary tree, return the postorder traversal of its nodes’ values. Postorder visits: left → right → root.

Given the root of a binary tree, return the preorder traversal of its nodes’ values. Preorder visits: root → left → right.

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path...

Given a binary tree, determine if it is height-balanced. A height-balanced binary tree is one in which the depth of the two subtrees of every node never differs by more...

Given an integer array nums of unique elements, return all possible subsets (the power set). The solution must not contain duplicate subsets.

Given an integer array nums and an integer k, return true if nums has a good subarray, i.e., a contiguous subarray of length at least 2 whose sum is a...