Q1: The Two Sneaky Numbers of Digitville In the town of Digitville, there was a list of numbers called nums containing integers from 0 to n - 1. Each number was supposed to appear exactly once in the list, however, two mischievous numbers sneaked in ...
Write a function that takes the binary representation of a positive integer and returns the number of set bits it has (also known as the Hamming weight). Thoughts This one is basically identical to 2220 kekw Solution class Solution { public int...
A bit flip of a number x is choosing a bit in the binary representation of x and flipping it from either 0 to 1 or 1 to 0. For example, for x = 7, the binary representation is 111 and we may choose any bit (including any leading zeros not shown) and...
Given the root of a binary tree, return its maximum depth. A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Thoughts As with a lot of tree algorithms I think the best solu...
Given the root of a binary tree, invert the tree, and return its root. Thoughts Seems like a pretty simple problem, I would imagine that doing this recursively would be the easiest way to go about it Simply swap the left and right nodes, then recur...
Given the head of a singly linked list, reverse the list, and return the reversed list. Thoughts Pretty easy, simple as iterating through the list and building the list in reverse order Solution /** * Definition for singly-linked list. * public c...
You are given an m x n integer matrix matrix with the following two properties: Each row is sorted in non-decreasing order. The first integer of each row is greater than the last integer of the previous row. Given an integer target, return true i...
Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You must write an algorithm with O(log n) runtime com...
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the cor...