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LeetCode #21: Merge Two Sorted Lists

Oct 15, 2022CodeCatch
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quick sort

Nov 19, 2022CodeCatch

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import java.util.Arrays;
public class QuickSortMain {
private static int array[];
public static void sort(int[] arr) {
if (arr == null || arr.length == 0) {
return;
}
array = arr;
quickSort(0, array.length-1);
}
private static void quickSort(int left, int right) {
int i = left;
int j = right;
// find pivot number, we will take it as mid
int pivot = array[left+(right-left)/2];
while (i <= j) {
/**
* In each iteration, we will increment left until we find element greater than pivot
* We will decrement right until we find element less than pivot
*/
while (array[i] < pivot) { i++; } while (array[j] > pivot) {
j--;
}
if (i <= j) {
exchange(i, j);
//move index to next position on both sides
i++;
j--;
}
}
// call quickSort() method recursively
if (left < j)
quickSort(left, j);
if (i < right)
quickSort(i, right);
}
private static void exchange(int i, int j) {
int temp = array[i];
array[i] = array[j];
array[j] = temp;
}
public static void main(String a[]){
int[] input = {33,21,45,64,55,34,11,8,3,5,1};
System.out.println("Before Sorting : ");
System.out.println(Arrays.toString(input));
sort(input);
System.out.println("==================");
System.out.println("After Sorting : ");
System.out.println(Arrays.toString(array));
}
}

Heap sort

Nov 19, 2022CodeCatch

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import java.util.*;
public class HeapSortMain {
public static void buildheap(int []arr) {
/*
* As last non leaf node will be at (arr.length-1)/2
* so we will start from this location for heapifying the elements
* */
for(int i=(arr.length-1)/2; i>=0; i--){
heapify(arr,i,arr.length-1);
}
}
public static void heapify(int[] arr, int i,int size) {
int left = 2*i+1;
int right = 2*i+2;
int max;
if(left <= size && arr[left] > arr[i]){
max=left;
} else {
max=i;
}
if(right <= size && arr[right] > arr[max]) {
max=right;
}
// If max is not current node, exchange it with max of left and right child
if(max!=i) {
exchange(arr,i, max);
heapify(arr, max,size);
}
}
public static void exchange(int[] arr,int i, int j) {
int t = arr[i];
arr[i] = arr[j];
arr[j] = t;
}
public static int[] heapSort(int[] arr) {
buildheap(arr);
int sizeOfHeap=arr.length-1;
for(int i=sizeOfHeap; i>0; i--) {
exchange(arr,0, i);
sizeOfHeap=sizeOfHeap-1;
heapify(arr, 0,sizeOfHeap);
}
return arr;
}
public static void main(String[] args) {
int[] arr={1,10,16,19,3,5};
System.out.println("Before Heap Sort : ");
System.out.println(Arrays.toString(arr));
arr=heapSort(arr);
System.out.println("=====================");
System.out.println("After Heap Sort : ");
System.out.println(Arrays.toString(arr));
}
}

longest sequence

Oct 7, 2023AustinLeath

0 likes • 5 views

import java.util.Arrays;
public class LongestIncreasingSubsequence {
public int lengthOfLIS(int[] nums) {
if (nums.length == 0) {
return 0;
}
int[] dp = new int[nums.length];
Arrays.fill(dp, 1); // Initialize all elements in dp array to 1, as each element itself is a valid subsequence of length 1.
int maxLength = 1; // Initialize the maximum length to 1, considering a single element as the sequence.
for (int i = 1; i < nums.length; i++) {
for (int j = 0; j < i; j++) {
if (nums[i] > nums[j]) {
dp[i] = Math.max(dp[i], dp[j] + 1); // If nums[i] is greater than nums[j], update the longest subsequence length ending at i.
}
}
maxLength = Math.max(maxLength, dp[i]); // Update the maximum length if needed.
}
return maxLength;
}
public static void main(String[] args) {
LongestIncreasingSubsequence lis = new LongestIncreasingSubsequence();
int[] nums = {10, 9, 2, 5, 3, 7, 101, 18};
int result = lis.lengthOfLIS(nums);
System.out.println("Length of the Longest Increasing Subsequence: " + result); // Output: 4
}
}

Puzzle 1

Feb 6, 2021Daedalus

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import java.util.Scanner;
/* In Heaven, the seed is tall and the oak small / It's input vital
* "The al-Madinatian," verse 236-37
* tinyurl.com/17snqkfv
* email answer to [email protected]
**/
public class Main
{
public static void main(String args[])
{
int x = 0;
int a, c, m = 10000;
Scanner in = new Scanner(System.in);
System.out.println("Please enter a seed, maximum 3000000:");
x = in.nextInt();
System.out.println("Please input a number, maximum 29:");
a = in.nextInt();
System.out.println("Please input a number, maximum 999999:");
c = in.nextInt();
char menu = 'y';
while(menu != 'n')
{
x = (a*x + c) % m;
System.out.println("The next number is " + x + "\nWould you like another? (y/n)");
menu = in.next().charAt(0);
}
}
}
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//██║  ██╔══██║██║╚██╔╝██║  ██║░░██║██╔══██║██╔══╝░░██║░░██║██╔══██║██║░░░░░██║░░░██║░╚═══██╗
//██║  ██║░░██║██║░╚═╝░██║  ██████╔╝██║░░██║███████╗██████╔╝██║░░██║███████╗╚██████╔╝██████╔╝
//╚═╝  ╚═╝░░╚═╝╚═╝░░░░░╚═╝  ╚═════╝░╚═╝░░╚═╝╚══════╝╚═════╝░╚═╝░░╚═╝╚══════╝░╚═════╝░╚═════╝░

Send Email from Java

Nov 19, 2022CodeCatch

0 likes • 5 views

import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException
{
boolean debug = false;
//Set the host smtp address
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.example.com");
// create some properties and get the default Session
Session session = Session.getDefaultInstance(props, null);
session.setDebug(debug);
// create a message
Message msg = new MimeMessage(session);
// set the from and to address
InternetAddress addressFrom = new InternetAddress(from);
msg.setFrom(addressFrom);
InternetAddress[] addressTo = new InternetAddress[recipients.length];
for (int i = 0; i < recipients.length; i++)
{
addressTo[i] = new InternetAddress(recipients[i]);
}
msg.setRecipients(Message.RecipientType.TO, addressTo);
// Optional : You can also set your custom headers in the Email if you Want
msg.addHeader("MyHeaderName", "myHeaderValue");
// Setting the Subject and Content Type
msg.setSubject(subject);
msg.setContent(message, "text/plain");
Transport.send(msg);
}

Factorial

Nov 19, 2022CodeCatch

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public class Factorial
{
public static void main(String[] args)
{ final int NUM_FACTS = 100;
for(int i = 0; i < NUM_FACTS; i++)
System.out.println( i + "! is " + factorial(i));
}
public static int factorial(int n)
{ int result = 1;
for(int i = 2; i <= n; i++)
result *= i;
return result;
}
}