House Robber IIIThe thief has found himself a new place for his thievery again. There is only one entrance to this area, called the “root.” Besides the root, each house has one and only one parent ho
Increasing Triplet SubsequenceGiven an unsorted array return whether an increasing subsequence of length 3 exists or not in the array. Formally the function should: Return true if there exists i, j,
Reconstruct ItineraryGiven 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 depa
Verify Preorder Serialization of a Binary TreeOne way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node’s value. If it is a null node, we
Odd Even Linked ListGiven 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. You shou
Coin ChangeYou are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amou
Bulb SwitcherThere 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 o
Maximum Product of Word LengthsGiven 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 w
Super Ugly NumberWrite a program to find the nth super ugly number. Super ugly numbers are positive numbers whose all prime factors are in the given prime list primes of size k. For example, [1, 2, 4
Minimum Height TreesFor a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum h
Best Time to Buy and Sell Stock with CooldownSay you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete a
Range Sum Query - MutableGiven an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. The update(i, val) function modifies nums by updating the element at ind
Additive NumberAdditive number is a string whose digits can form additive sequence. A valid additive sequence should contain at least three numbers. Except for the first two numbers, each subsequent
Range Sum Query 2D - ImmutableGiven a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2). The abov
Longest Increasing SubsequenceGiven an unsorted array of integers, find the length of longest increasing subsequence. For example:Given [10, 9, 2, 5, 3, 7, 101, 18],The longest increasing subsequence