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Best Time to Buy and Sell Stock II

▼  June (12)

Generate Parentheses (Java)

Climbing Stairs

Best Time to Buy and Sell Stock (Java)

Unique Paths Java

Binary Tree Postorder Traversal (Java)

Permutations (Java)

Minimum Path Sum (Java)

Search a 2D Matrix (Java + Python)

Container With Most Water

Remove Duplicates from Sorted Array II (Python + J…

Spiral Matrix II ( Java +…

Stock buy and sell

public class StockBuySell { public static void main(String[] args) { int prices[] = { 100, 180, 260, 310, 40, 535, 695 }; stockBuySell(prices); bestBuySell(prices); } public static void bestBuySell(int[] prices) { int d = 0; int max = 0; for (int i = 1; i < prices.length; i++) { d = prices[i] - prices[i - 1] + Math.max(d, 0); if (d > max) max = d; } System.out.println(max); } private static void…

Anagram Finder from given string java

Map<String, List<String>> words = new HashMap<String, List<String>>(); for(String word : incomingWords) { final String key = alphabetize(word); if(words.contains(key)){ words.get(key).add(word); } else { words.put(key, new ArrayList<String>()); words.get(key).add(word); } } //alphabetize //char[] chars = word.toCharArray(); //Arrays.sort(chars);

import java.util.Scanner; public class PascalTriangle { public static void print(int n) { for (int i = 0; i < n; i++) { for (int j = 0; j <= i; j++) { System.out.print(pascal(i, j) + " "); } System.out.println(); } } public static int pascal(int i, int j) { if (j == 0) { return 1; } else if (j == i) { return 1; } else { return pascal(i - 1, j - 1) + pascal(i - 1, j); } } public static void…

squareroot of given number

public class SquareRootDemo { public static void main(String[] args) { //Number for which square root is to be found double number = 10; //This method finds out the square root findSquareRoot(number); } /*This method finds out the square root without using any built-in functions and displays it */ public static void findSquareRoot(double number) { boolean isPositiveNumber = true; double guess;…

Detect loop in the linked list

boolean hasLoop(Node first) { if(first == null) // list does not exist..so no loop either. return false; Node slow, fast; // create two references. slow = fast = first; // make both refer to the start of the list. while(true) { slow = slow.next; // 1 hop. if(fast.next != null) fast = fast.next.next; // 2 hops. else return false; // next node null => no loop. if(slow == null || fast == null) // if…

Find the mid point of linked list by scanning list only once

Node findMiddlePoint(Node list) { Node m = list; while(list != NULL && list->next != NULL) { m = m->next; list = list->next->next; } return m; }

tough interview questions and answers

50: Insert Value into Sorted Circular Linked List

49: Print Longest Increasing Subsequence (LIS) using Dynamic Programming

48: Compute Largest Contiguous Subsequent Product (LSP) in Linear Time

47: Binary Tree Postorder Traversal without recursion (using stack)

46: N-Queen Problem

45: Print a full binary tree’s boundary in counterclockwise order

44: Given pre-order traversal, print all possible…

How to find pair with kth largest sum?

Given two sorted arrays of numbers, we want to find the pair with the kth largest possible sum. (A pair is one element from the first array and one element from the second array). For example, with arrays

[2, 3, 5, 8, 13]

[4, 8, 12, 16]

The pairs with largest sums are

13 + 16 = 29

13 + 12 = 25

8 + 16 = 24

13 + 8 = 21

8 + 12 = 20

So the pair with the 4th largest sum is (13, 8). How to find the…

BFS and DFS java

Class Main { public void bfs() { // BFS uses Queue data structure Queue queue = new LinkedList(); queue.add(this.rootNode); printNode(this.rootNode); rootNode.visited = true; while(!queue.isEmpty()) { Node node = (Node)queue.remove(); Node child=null; while((child=getUnvisitedChildNode(node))!=null) { child.visited=true; printNode(child); queue.add(child); } } // Clear visited property of nodes…

Setup:Assume primitive Facebook. FB has Members.classMember{String name;String email;List<Member> friends;}

Question: Code printSocialGraph(Member m). Direct friends of m are Level 1 friends. Friends of friends are level 2 friends…..and so on Print level 1 friends first. Then print level 2 friends….and so on

void printSocialGraph (Member m){//Your code here}

    Solution:

  BFS

Processes and Threads

In concurrent programming, there are two basic units of execution: processes and threads. In the Java programming language, concurrent programming is mostly concerned with threads. However, processes are also important.

A computer system normally has many active processes and threads. This is true even in systems that only have a single execution core, and thus only have…

Weighted randomness in Java

In Java, given n Items, each with weight w, how does one choose a random Item from the collection with a chance equal to w?

Assume each weight is a double from 0.0 to 1.0, and that the weights in the collection sum to 1. Item.getWeight() returns the Item’s weight.

Item[] items = ...; // Compute the total weight of all items together double totalWeight = 0.0d; for (Item i : items) { totalWeight…

1) If right subtree of node is not NULL, then succ lies in right subtree. Do following. Go to right subtree and return the node with minimum key value in right subtree. 2) If right sbtree of node is NULL, then succ is one of the ancestors. Do following. Travel up using the parent pointer until you see a node which is left child of it’s parent. The parent of such a node is the succ.

search for the rotation pivot in roated sorted array

int FindSortedArrayRotation(int A[], int N) { int L = 0; int R = N - 1; while (A[L] > A[R]) { int M = L + (R - L) / 2; if (A[M] > A[R]) L = M + 1; else R = M; } return L; }

Given an array and a value, find if there is a triplet in array whose sum is equal to the given value. If there is such a triplet present in array, then print the triplet and return true. Else return false. For example, if the given array is {12, 3, 4, 1, 6, 9} and given sum is 24, then there is a triplet (12, 3 and 9) present in array whose sum is 24.

    public static boolean threeSumTo(int[]…

1) What is the difference between Serializable and Externalizable interface in Java?

This is most frequently asked question in Java serialization interview. Here is my version Externalizable provides us writeExternal() and readExternal() method which gives us flexibility to control java serialization mechanism instead of relying on Java’s default serialization. Correct implementation…