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Java Exercises: Merge two given sorted lists

Java Basic: Exercise-143 with Solution

Write a Java program to merge two given sorted lists.

Sample Solution:

Java Code:

public class Solution {
    public static void main(String[] args) {
        ListNode list1 = new ListNode(1);
        list1.next = new ListNode(3);
        list1.next.next = new ListNode(7);
        list1.next.next.next = new ListNode(9);
        list1.next.next.next.next = new ListNode(13);
        ListNode list2 = new ListNode(2);
        list2.next = new ListNode(40);
        ListNode head = mergeTwoLists(list1, list2);
		System.out.print("Merge Two Sorted ListsT:\n");
        while (head != null) {
            System.out.print(head.val + " ");
            head = head.next;
        }
    }

    public static ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        ListNode head = new ListNode(0);
        ListNode mlist = head;
        while (list1 != null && list2 != null) {
            if (list1.val < list2.val) {
                mlist.next = new ListNode(list1.val);
                mlist = mlist.next;
                list1 = list1.next;
            } else {
                mlist.next = new ListNode(list2.val);
                mlist = mlist.next;
                list2 = list2.next;
            }
        }
        while (list1 != null) {
            mlist.next = new ListNode(list1.val);
            mlist = mlist.next;
            list1 = list1.next;
        }
        while (list2 != null) {
            mlist.next = new ListNode(list2.val);
            mlist = mlist.next;
            list2 = list2.next;
        }

        head = head.next;
        return head;
    }
}

class ListNode {
    int val;
    ListNode next;

    ListNode(int val) {
        this.val = val;
        this.next = null;
    }
}

Sample Output: 

Merge Two Sorted ListsT:
1 2 3 7 9 13 40

Flowchart:

Flowchart: Java exercises: Merge two given sorted lists.

Java Code Editor:

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Next: Write a Java program to remove all occurrences of a specified value in a given array of integers and return the new length of the array.

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Java: Tips of the Day

Execution of console commands:

Java allows you to execute console commands directly from code using a class Runtime. It is very important not to forget about exception handling.

For example, let's try to open a PDF file through a Java terminal:

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
  
public class ShellCommandExec {
  
  public static void main(String[] args) {
    String gnomeOpenCommand = "gnome-open //home//user//Documents//MyDoc.pdf";
  
    try {
      Runtime rt = Runtime.getRuntime();
      Process processObj = rt.exec(gnomeOpenCommand);
  
      InputStream stdin = processObj.getErrorStream();
      InputStreamReader isr = new InputStreamReader(stdin);
      BufferedReader br = new BufferedReader(isr);
  
      String myoutput = "";
  
      while ((myoutput=br.readLine()) != null) {
        myoutput = myoutput+"\n";
      }
      System.out.println(myoutput);
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }
}