Robina Li

Given two sparse vectors, compute their dot product.

You are given two integer arrays nums1 and nums2. You are tasked to implement a data structure that supports the following operations:

Given the root of a binary tree and an integer targetSum, return the number of paths where the sum of the values along the path equals targetSum.

Given an encoded string, return its decoded string.

There is an m x n rectangular island that borders both the Pacific Ocean and the Atlantic Ocean. The Pacific Ocean touches the island’s left and top edges, and the...

You are given an array of people, people, which are the attributes of some people in a queue (not necessarily in order). Each people[i] = [hi, ki] represents the ith...

The minimum product of a subarray is the minimum value in the subarray multiplied by the sum of the subarray.

Given a string s, remove duplicate letters so that every letter appears once and only once. You must make sure your result is the smallest in lexicographical order among all...

In English, we have a concept called root, which can be followed by some other word to form another longer word. Let’s call this word successor. For example, when the...

Given an integer array nums, return the length of the longest strictly increasing subsequence.