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

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

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.

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.

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

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

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.

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

Given an integer array sorted in ascending order, write a function to search target in nums. If target exists, then return its index, otherwise return -1. However, the array size is unknown to you. You may only access the array using an ArrayReader interface, where ArrayReader.get(k) returns the ...

Given an unsorted array nums, reorder it in-place such that nums[0] <= nums[1] >= nums[2] <= nums[3]....

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list.

Given a binary array, find the maximum number of consecutive 1s in this array if you can flip at most one 0.

You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.

Given an unsorted integer array, find the smallest missing positive integer.

Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn't one, return 0 instead.

Given an array with n integers, you need to find if there are triplets (i, j, k) which satisfies following conditions:

A.length >= 3There exists some 0 < i < A.length - 1 such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1]Given an array that is definitely a mountain, return any i such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.leng...

Given an array of integers nums, write a method that returns the "pivot" index of this array.

The API: int read4(char *buf) reads 4 characters at a time from a file.

Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 <= i <= N) in this array:

Given an integer array, find three numbers whose product is maximum and output the maximum product.

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

In a row of seats, 1 represents a person sitting in that seat, and 0 represents that the seat is empty.

Given an unsorted array of integers, find the length of longest continuous increasing subsequence (subarray).

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (si < ei), find the minimum number of conference rooms required.

An array is monotonic if it is either monotone increasing or monotone decreasing.

Given an array consists of non-negative integers, your task is to count the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle.Example 1:Input: [2,2,3,4]Output: 3Explanation:Valid combinations are: 2,3,4 (using the first 2)2,3,4 (using t...

Suppose you are at a party with n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. The definition of a celebrity is that all the other n - 1 people know him/her but he/she does not know any of them.

Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1.

The length after compression must always be smaller than or equal to the original array.