Robina Li

We can “shift” a string by shifting each character to its successive character (with z wrapping to a). For example, "abc" can be shifted to "bcd", …, "xyz", "yza", "zab"....

Given two strings ransomNote and magazine, return true if ransomNote can be constructed by using the letters from magazine. Each letter in magazine can only be used once.

Given two strings s and t, return true if t is an anagram of s, and false otherwise. An anagram uses the exact same characters with the exact same frequencies....

Given an integer array nums and an integer k, return true if there are two distinct indices i and j such that nums[i] == nums[j] and abs(i - j) <=...

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.