Java Archives - Page 20 of 25

Contains Duplicate II

Nov

25

2015

Title: Contains Duplicate II Source: leetcode.com Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. Java solution Java /* https://leetcode.com/problems/contains-duplicate-ii/ */ import java.util.HashMap; public class ...

Contains Duplicate

Nov

25

2015

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

Nov

25

2015

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

Nov

25

2015

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 = ...

Climbing Stairs

Nov

25

2015

Title: Climbing Stairs Source: leetcode.com You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Java solution Java /* https://leetcode.com/problems/climbing-stairs/ */ import java.util.HashSet; class ClimbStairs { HashSet set = ...

Binary Tree Paths

Nov

25

2015

Title: Binary Tree Paths Source: leetcode.com Given a binary tree, return all root-to-leaf paths. For example, given the following binary tree: 1 / \ 2 3 \ 5 12345 1 / \2 3 \ 5 All root-to-leaf paths are: ["1->2->5", "1->3"] 1 ["1->2->5", "1->3"] Java solution Java /* https://leetcode.com/problems/binary-tree-paths/ */ import java.util.List; import java.util.ArrayList; public ...

Add Digits

Nov

25

2015

Title: Add Digits Source: leetcode.com Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it. Follow up: Could you do ...

Bulls and Cows

Nov

22

2015

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

Dec

5

2014

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

Nov

27

2014

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 ...