Contains Duplicate

Title: Contains Duplicate Source: leetcode.com Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. Java solution Java /* https://leetcode.com/problems/contains-duplicate/ */ import java.util.HashSet; public class ContainsDuplicate { public ...

Container With Most Water

Title: Container With Most Water Source: leetcode.com Given n non-negative integers a1, a2, …, an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such ...

Clone Graph

Title: Clone Graph Source: leetcode.com Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. Nodes are labeled uniquely. Java solution Java /* https://leetcode.com/problems/clone-graph/ */ import java.util.HashMap; import java.util.List; import java.util.ArrayList; public class CloneGraph { public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) { if(node==null) return null; HashMap<Integer, UndirectedGraphNode> visited = ...

Bulls and Cows

Title: Bulls and Cows Source: leetcode.com You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time your friend makes a guess, you provide a hint that indicates how many digits in said guess match your secret ...

Find maximal uni-directional path length for a Binary Tree 1

Find maximal uni-directional path length for a Binary Tree
Continuing from our last post for a Generic Binary Tree implementation, we’ve come up with a solution to quite an interesting problem. We define a path in a binary tree to be a non-empty sequence of nodes that one can traverse by following the pointers in the nodes. A path only goes to the right ...

Implementing a Generic Binary Tree in Java 2

Implementing a Generic Binary Tree in Java
The following two classes demonstrate an implementation of the Generic Binary Tree data structure. The first class is BinaryTreeNode.java which acts as the node class for the tree, holding integer type data and two pointers for left and right child respectively of type same as the node class itself. The member fields are declared to ...

Structure vs Union in C – Coded Approach

Hello Everyone, Today we are going to talk a bit about the difference between structure and union as in C programming language. We are going to provide a coded approach so that you could see the difference practically as the theoretic differences you can read from anywhere on the internet and your text books. Here ...

Add Two Integers without using Arithmetic Operators

Recently came across an interesting question of adding two numbers without using any of the arithmetic operators and thought of giving it a try. The first thought of solving the question was using bit-manipulation operations. The idea was to add the numbers bit-by-bit taking any carry forward (without actually adding them and instead using bit-wise ...

Lexicographically Bigger String

The following piece of code accepts as input a single string of characters and produces on standard output a string which would be the next string to appear in lexicographical order. Definition of Lexicographical order : wiki (Also known as The Dictionary order since lexicographical order is one in which the strings would appear in ...

Check if a number is Fibonacci

A Fibonacci number is one which appears in the Fibonacci Sequence. To check if a given number n occurs in the Fibonacci Sequence or not we only need to check if one or both of (5*n^2 + 4) or (5*n^2 – 4) is a perfect square or not (source: wiki). Python code for the same: ...