### [LeetCode] 958. Check Completeness of a Binary Tree

Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. It can have between 1 and 2^h nodes inclusive at the last level h.

### [LeetCode] 223. Rectangle Area

Find the total area covered by two rectilinear rectangles in a 2D plane.

### [LeetCode] 448. Find All Numbers Disappeared in an Array

Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.

### [LeetCode] 442. Find All Duplicates in an Array

Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.

### [LeetCode] 328. Odd Even Linked List

Given a singly linked list, group all odd nodes together followed by the even nodes. Please note here we are talking about the node number and not the value in the nodes.

### [LeetCode] 937. Reorder Log Files

You have an array of logs. Each log is a space delimited string of words.

### [LeetCode] 84. Largest Rectangle in Histogram

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.

### [LeetCode] 287. Find the Duplicate Number

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.

### [LeetCode] 165. Compare Version Numbers

Compare two version numbers version1 and version2.If version1 &gt; version2 return 1; if version1 &lt; version2 return -1;otherwise return 0.

### [LeetCode] 545. Boundary of Binary Tree

Given a binary tree, return the values of its boundary in anti-clockwise direction starting from root. Boundary includes left boundary, leaves, and right boundary in order without duplicate nodes.

### [LeetCode] 59. Spiral Matrix II

Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

### [LeetCode] 605. Can Place Flowers

Suppose you have a long flowerbed in which some of the plots are planted and some are not. However, flowers cannot be planted in adjacent plots - they would compete for water and both would die.

### [LeetCode] 867. Transpose Matrix

The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix.

### [LeetCode] 475. Heaters

Winter is coming! Your first job during the contest is to design a standard heater with fixed warm radius to warm all the houses.

### [LeetCode] 617. Merge Two Binary Trees

Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not.

### [LeetCode] 905. Sort Array By Parity

Given an array A of non-negative integers, return an array consisting of all the even elements of A, followed by all the odd elements of A.

### [LeetCode] 709. To Lower Case

Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase.

### [LeetCode] 61. Rotate List

Given a linked list, rotate the list to the right by k places, where k is non-negative.

### [LeetCode] 51. N-Queens

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.

### [LeetCode] 97. Interleaving String

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.

### [LeetCode] 249. Group Shifted Strings

Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -&gt; "bcd". We can keep "shifting" which forms the sequence:

### [LeetCode] 332. Reconstruct Itinerary

Given a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in order. All of the tickets belong to a man who departs from JFK. Thus, the itinerary must begin with JFK.

### [LeetCode] 741. Cherry Pickup

In a N x N grid representing a field of cherries, each cell is one of three possible integers.

### [LeetCode] 417. Pacific Atlantic Water Flow

Given an m x n matrix of non-negative integers representing the height of each unit cell in a continent, the "Pacific ocean" touches the left and top edges of the matrix and the "Atlantic ocean" touches the right and bottom edges.

### [LeetCode] 364. Nested List Weight Sum II

Given a nested list of integers, return the sum of all integers in the list weighted by their depth.

### [LeetCode] 767. Reorganize String

Given a string S, check if the letters can be rearranged so that two characters that are adjacent to each other are not the same.

### [LeetCode] 115. Distinct Subsequences

Given a string S and a string T, count the number of distinct subsequences of S which equals T.

### [LeetCode] 181. Employees Earning More Than Their Managers

The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id.

### [LeetCode] 402. Remove K Digits

Given a non-negative integer num represented as a string, remove k digits from the number so that the new number is the smallest possible.