Posts

Leetcode 295: Find Median from Data Stream

Posted on August 1, 2018

Question Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value. [Read More]
Tags:
- Leetcode
- Hard
- Review
Leetcode 323: Number of Connected Components in an Undirected Graph

Posted on July 31, 2018

Question Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to find the number of connected components in an undirected graph. [Read More]
Tags:
- Leetcode
- BFS
Leetcode 320: Generalized Abbreviation

Posted on July 31, 2018

Question Write a function to generate the generalized abbreviations of a word. [Read More]
Tags:
- Leetcode
- DP
- Backtracking
Leetcode 672: Bulb Switcher II

Posted on July 31, 2018

Question There is a room with n lights which are turned on initially and 4 buttons on the wall. After performing exactly m unknown operations towards buttons, you need to return how many different kinds of status of the n lights could be. [Read More]
Tags:
- Leetcode
Leetcode 319: Bulb Switcher

Posted on July 31, 2018

Question There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you toggle every third bulb (turning on if it’s off or turning off if it’s on). For the i-th round, you toggle every... [Read More]
Tags:
- Leetcode
Leetcode 318: Maximum Product of Word Lengths

Posted on July 31, 2018

Question Given a string array words, find the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. You may assume that each word will contain only lower case letters. If no such two words exist, return 0. [Read More]
Tags:
- Leetcode
Leetcode 293: Flip Game

Posted on July 31, 2018

Question You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take turns to flip two consecutive "++" into "--". The game ends when a person can no longer make a move and therefore... [Read More]
Tags:
- Leetcode
Leetcode 289: Game of Life

Posted on July 31, 2018

Question According to the Wikipedia’s article: “The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970.” [Read More]
Tags:
- Leetcode
Leetcode 287: Find the Duplicate Number

Posted on July 30, 2018

Question Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. [Read More]
Tags:
- Leetcode
- Review
Leetcode 286: Walls and Gates

Posted on July 30, 2018

Question You are given a m x n 2D grid initialized with these three possible values. [Read More]
Tags:
- Leetcode
- BFS
Leetcode 285: Inorder Successor in BST

Posted on July 30, 2018

Question Given a binary search tree and a node in it, find the in-order successor of that node in the BST. [Read More]
Tags:
- Leetcode
Leetcode 284: Peeking Iterator

Posted on July 30, 2018

Question Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation – it essentially peek() at the element that will be returned by the next call to next(). [Read More]
Tags:
- Leetcode
Leetcode 281: Zigzag Iterator

Posted on July 30, 2018

Given two 1d vectors, implement an iterator to return their elements alternately. [Read More]
Tags:
- Leetcode
Leetcode 280: Wiggle Sort

Posted on July 30, 2018

Question Given an unsorted array nums, reorder it in-place such that nums[0] <= nums[1] >= nums[2] <= nums[3].... [Read More]
Tags:
- Leetcode
Leetcode 279: Perfect Squares

Posted on July 30, 2018

Question Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. [Read More]
Tags:
- Leetcode
- BFS
- Review

Leetcode 295: Find Median from Data Stream

Leetcode 323: Number of Connected Components in an Undirected Graph

Leetcode 320: Generalized Abbreviation

Leetcode 672: Bulb Switcher II

Leetcode 319: Bulb Switcher

Leetcode 318: Maximum Product of Word Lengths

Leetcode 293: Flip Game

Leetcode 289: Game of Life

Leetcode 287: Find the Duplicate Number

Leetcode 286: Walls and Gates

Leetcode 285: Inorder Successor in BST

Leetcode 284: Peeking Iterator

Leetcode 281: Zigzag Iterator

Leetcode 280: Wiggle Sort

Leetcode 279: Perfect Squares