Answers for "merge sort in java"

merge sort java

public static void mergeSort(int[] a, int n) {
    if (n < 2) {
        return;
    }
    int mid = n / 2;
    int[] l = new int[mid];
    int[] r = new int[n - mid];
 
    for (int i = 0; i < mid; i++) {
        l[i] = a[i];
    }
    for (int i = mid; i < n; i++) {
        r[i - mid] = a[i];
    }
    mergeSort(l, mid);
    mergeSort(r, n - mid);
 
    merge(a, l, r, mid, n - mid);
}

public static void merge(
  int[] a, int[] l, int[] r, int left, int right) {
 
    int i = 0, j = 0, k = 0;
    while (i < left && j < right) {
        if (l[i] <= r[j]) {
            a[k++] = l[i++];
        }
        else {
            a[k++] = r[j++];
        }
    }
    while (i < left) {
        a[k++] = l[i++];
    }
    while (j < right) {
        a[k++] = r[j++];
    }
}

how to write a merge sort array method ni java

public static void mergeSort(int[] a, int n) {
    if (n < 2) {
        return;
    }
    int mid = n / 2;
    int[] l = new int[mid];
    int[] r = new int[n - mid];
 
    for (int i = 0; i < mid; i++) {
        l[i] = a[i];
    }
    for (int i = mid; i < n; i++) {
        r[i - mid] = a[i];
    }
    mergeSort(l, mid);
    mergeSort(r, n - mid);
 
    merge(a, l, r, mid, n - mid);
}

how to write a merge sort array method ni java

public static void merge(
  int[] a, int[] l, int[] r, int left, int right) {
  
    int i = 0, j = 0, k = 0;
    while (i < left && j < right) {
        if (l[i] <= r[j]) {
            a[k++] = l[i++];
        }
        else {
            a[k++] = r[j++];
        }
    }
    while (i < left) {
        a[k++] = l[i++];
    }
    while (j < right) {
        a[k++] = r[j++];
    }
}

merge sort java

import java.util.Random;
import java.util.Scanner;

public class MergeSort {
    public static void main(String[] argh){
        Scanner scanner  = new Scanner(System.in);
        System.out.println("Enter the size of you victor: ");
        int size = scanner.nextInt();
        int[] unSortedArr = new int[size];
        unSortedArr = enterRandomValues(unSortedArr);
        int[] sortedARR = loop(unSortedArr);
        print(sortedARR);
    }
    public static int[] loop(int[] unSortedArr){
        for(int start = 0 ; start < unSortedArr.length ; ++start){
            int minIndex = findTheMiniIndex(unSortedArr,start);
            swap(unSortedArr,minIndex,start);
        }

        return unSortedArr ;
    }

    public static int findTheMiniIndex(int[] arr, int start){
        int index = start;
        for(int i = start+1 ; i < arr.length ; ++i){
            if(arr[index]>arr[i]){
                index = i ;
            }
        }

        return index;
    }

    public static void swap(int[] swapValOfArr,int minIndex,int start){
        int temp = swapValOfArr[minIndex];
        swapValOfArr[minIndex]= swapValOfArr[start]  ;
        swapValOfArr[start] = temp ;

    }

    public static void print(int[] sorteArr){
        for(int i = 0 ; i < sorteArr.length ; ++i) {
            System.out.println(sorteArr[i]);
        }
    }

    public static int[] enterRandomValues(int[] unSortedArr){
        Random random = new Random();
        for(int i = 0 ; i< unSortedArr.length; ++i){
            unSortedArr[i] =random.nextInt(1000);
        }
        return unSortedArr;
    }
}

Merge sort java

public class JavaMergeSort
{
   void sorting(int[] num, int left, int main, int right)
   {
      // finding size of two sub arrays
      int list1 = main - left + 1;
      int list2 = right - main;
      // creating temporary array
      int[] L = new int[list1];
      int[] R = new int[list2];
      // copying data to temporary array
      for(int a = 0; a < list1; ++a)
         L[a] = num[left + a];
      for(int b = 0; b < list2; ++b)
         R[b] = num[main + 1+ b];
      // existing index of first and second sub array
      int p = 0, q = 0;
      // existing index of merged sub array
      int r = left;
      while(p < list1 && q < list2)
      {
         if(L[p] <= R[q])
         {
            num[r] = L[p];
            p++;
         }
         else
         {
            num[r] = R[q];
            q++;
         }
         r++;
      }
      // copying remaining elements of L[] array
      while(p < list1)
      {
         num[r] = L[p];
         p++;
         r++;
      }
      // copying remaining elements of R[] array
      while(q < list2)
      {
         num[r] = R[q];
         q++;
         r++;
      }
   }
   // function that sorts
   void sort(int[] arrNum, int l, int r)
   {
      if(l < r)
      {
         // finding middle point
         int m = (l + r) / 2;
         // sorting first and second list
         sort(arrNum, l, m);
         sort(arrNum , m+1, r);
         // merging sorted list
         sorting(arrNum, l, m, r);
      }
   }
   // display array
   static void displayArray(int[] arr)
   {
      int number = arr.length;
      for(int a = 0; a < number; ++a)
         System.out.print(arr[a] + " ");
      System.out.println();
   }
   public static void main(String[] args)
   {
      int[] arrNumbers = {33, 00, 55, 11, 22, 44};
      System.out.println("Before sorting - ");
      displayArray(arrNumbers);
      JavaMergeSort obj = new JavaMergeSort();
      obj.sort(arrNumbers, 0, arrNumbers.length - 1);
      System.out.println("\nAfter sorting - ");
      displayArray(arrNumbers);
   }
}

merge sort

// @see https://www.youtube.com/watch?v=es2T6KY45cA&vl=en
// @see https://www.cs.usfca.edu/~galles/visualization/ComparisonSort.html

function merge(list, start, midpoint, end) {
    const left = list.slice(start, midpoint);
    const right = list.slice(midpoint, end);
    for (let topLeft = 0, topRight = 0, i = start; i < end; i += 1) {
        if (topLeft >= left.length) {
            list[i] = right[topRight++];
        } else if (topRight >= right.length) {
            list[i] = left[topLeft++];
        } else if (left[topLeft] < right[topRight]) {
            list[i] = left[topLeft++];
        } else {
            list[i] = right[topRight++];
        }
    }
}

function mergesort(list, start = 0, end = undefined) {
    if (end === undefined) {
        end = list.length;
    }
    if (end - start > 1) {
        const midpoint = ((end + start) / 2) >> 0;
        mergesort(list, start, midpoint);
        mergesort(list, midpoint, end);
        merge(list, start, midpoint, end);
    }
    return list;
}

mergesort([4, 7, 2, 6, 4, 1, 8, 3]);