Reverse merge the half linked list

Write the production level code to arrange the linked list as given example:

1->2->3->4->5->6, make the following changes 1->6->2->5->3->4.

class Node {

     int value; Node next;

     public Node(intvalue) {

           this.value = value;

     }

}

public class ArrangeSuffledList {

     private static void getReversedSuffledList(Node head) {

           if(head==null|| head.next==null) {

                printList(head);

                return;

           }

          

           Node end = head.next;

           int length = 1;

           while(end != null) {

                end = end.next;

                length++;

           }

           Node mid = head.next;

           for (inti = 0; i < length/2-1; i++) {

                mid = mid.next;

           }

           //printList(mid);

           Node head2 = new Node(mid.value);

           Node next = mid.next;

           for (inti = 0; i < length-length/2-1; i++) {

                Node tNext = next.next;

                next = new Node(next.value);

                Node temp = next;

                temp.next = head2;

                head2 = temp;

                next = tNext;       

           }

           printList(mergeList(head, head2, length));

     }

     private static Node mergeList(Node head1, Node head2, int length) {

           Node head = new Node(head1.value);

           head.next = new Node(head2.value);

           Node next = head.next;

           int count = 2;

           head1 = head1.next;

           head2 = head2.next;

           while(head2!=null) {

                Node temp = newNode(head1.value);

                next.next = temp;

                next = next.next;

                count++;

                if(count<length) {

                     temp = newNode(head2.value);

                     next.next = temp;

                     next = next.next;

                     count++;

                }

                head1 = head1.next;

                head2 = head2.next;

           }

           return head;

     }

     public static void main(String[] args) {

           Node head = new Node(1);

           head.next = new Node(2);

           head.next.next = new Node(3);

           head.next.next.next = new Node(4);

           head.next.next.next.next = new Node(5);

           head.next.next.next.next.next = new Node(6);

           //head.next.next.next.next.next.next = new Node(7);

           /* 1->2->3->4->5->6 :: 1->6->2->5->3->4 * */

           getReversedSuffledList(head);

           //printList(head);

     }

     private static void printList(Node head) {

           System.out.println("");

           Node next = null;

           if(head!=null) {

                System.out.print(head.value+" ");

                next = head.next;

           }

           while(next!=null) {

                System.out.print(next.value+" ");

                next = next.next;

           }

     }

}

Find the Leaders in an array

An element is leader if it is greater than all the elements to its right side.

Example: Leaders in the array {18, 19, 7, 4, 6, 2} are 2, 6, 7 and 19.

 

public classLeadersInArray {

     public static voidmain(String[] args) {

           int[] array = {18, 19, 7, 4, 6, 2};

 

           int max = Integer.MIN_VALUE;

 

           for(int i=array.length-1;i>=0;i--) {

                if(array[i]>max) {

                     System.out.print(array[i]+" ");

                     max = array[i];

                }

           }

     }

}

K’th Non-repeating Character in a String using Java

1. Create an empty hash.

2. Scan input string from left to right and insert values and their counts in the hash.

for (char ch : array) {

     if(map.containsKey(ch)) {

          map.put(ch, map.get(ch)+1);

     } else {

          map.put(ch, 1);

     }

}

3. Scan input string from left to right and initialize the count by kth character and decrease it for every character has count 1 and return the character when count becomes 0.

importjava.util.HashMap;

importjava.util.Map;

public classKthNonRepeatChar {

   private static chargetKthNonoRepeatChar(String str,int kthRepeat) {

     

      char[] array = str.toCharArray();

      Map<Character, Integer> map = new HashMap<>();

      for (char ch : array) {

         if(map.containsKey(ch)) {

            map.put(ch, map.get(ch)+1);

         } else {

            map.put(ch, 1);

         }

      }

      for (char c : array) {

         if(map.get(c)==1) {

            kthRepeat --;

         }

         if(kthRepeat==0) {

            return c;

         }

      }

      return 0;

   }

   public static voidmain(String[] args) {

      String str = "thisissamplestring";

      int kthNonRepeat = 4;

      char character = getKthNonoRepeatChar(str,kthNonRepeat);

      System.out.println(character);

   }

}