Given a permutation arrays A[] consisting of N numbers in range [1, N], the task is to left rotate all the even numbers and right rotate all the odd numbers of the permutation and print the updated permutation.
Note: N is always even.
Examples:
Input: A = {1, 2, 3, 4, 5, 6, 7, 8}
Output: {7, 4, 1, 6, 3, 8, 5, 2}
Explanation:
Even element = {2, 4, 6, 8}
Odd element = {1, 3, 5, 7}
Left rotate of even number = {4, 6, 8, 2}
Right rotate of odd number = {7, 1, 3, 5}
Combining Both odd and even number alternatively.
Input: A = {1, 2, 3, 4, 5, 6}
Output: {5, 4, 1, 6, 3, 2}
Approach:
- It is clear that the odd elements are always on even index and even elements are always laying on odd index.
- To do left rotation of even number we choose only odd indices.
- To do right rotation of odd number we choose only even indices.
- Print the updated array.
Below is the implementation of the above approach:
C++
// C++ program to implement// the above approach#include<bits/stdc++.h>using namespace std;// function to left rotatevoid left_rotate(int arr[]){ int last = arr[1]; for (int i = 3; i < 6; i = i + 2) { arr[i - 2] = arr[i]; } arr[6 - 1] = last;}// function to right rotatevoid right_rotate(int arr[]){ int start = arr[6 - 2]; for (int i = 6- 4; i >= 0; i = i - 2) { arr[i + 2] = arr[i]; } arr[0] = start;}// Function to rotate the arrayvoid rotate(int arr[]){ left_rotate(arr); right_rotate(arr); for (int i = 0; i < 6; i++) { cout << (arr[i]) << " "; }}// Driver codeint main(){ int arr[] = { 1, 2, 3, 4, 5, 6 }; rotate(arr);}// This code is contributed by rock_cool |
Java
// Java program to implement// the above approachimport java.io.*;import java.util.*;import java.lang.*;class GFG { // function to left rotate static void left_rotate(int[] arr) { int last = arr[1]; for (int i = 3; i < arr.length; i = i + 2) { arr[i - 2] = arr[i]; } arr[arr.length - 1] = last; } // function to right rotate static void right_rotate(int[] arr) { int start = arr[arr.length - 2]; for (int i = arr.length - 4; i >= 0; i = i - 2) { arr[i + 2] = arr[i]; } arr[0] = start; } // Function to rotate the array public static void rotate(int arr[]) { left_rotate(arr); right_rotate(arr); for (int i = 0; i < arr.length; i++) { System.out.print(arr[i] + " "); } } // Driver code public static void main(String[] args) { int arr[] = { 1, 2, 3, 4, 5, 6 }; rotate(arr); }} |
Python3
# Python3 program for the above approach # Function to left rotate def left_rotate(arr): last = arr[1]; for i in range(3, len(arr), 2): arr[i - 2] = arr[i] arr[len(arr) - 1] = last# Function to right rotate def right_rotate(arr): start = arr[len(arr) - 2] for i in range(len(arr) - 4, -1, -2): arr[i + 2] = arr[i] arr[0] = start# Function to rotate the array def rotate(arr): left_rotate(arr) right_rotate(arr) for i in range(len(arr)): print(arr[i], end = " ")# Driver code arr = [ 1, 2, 3, 4, 5, 6 ] rotate(arr); # This code is contributed by sanjoy_62 |
C#
// C# program to implement// the above approachusing System;class GFG{// Function to left rotatestatic void left_rotate(int[] arr){ int last = arr[1]; for(int i = 3; i < arr.Length; i = i + 2) { arr[i - 2] = arr[i]; } arr[arr.Length - 1] = last;}// Function to right rotatestatic void right_rotate(int[] arr){ int start = arr[arr.Length - 2]; for(int i = arr.Length - 4; i >= 0; i = i - 2) { arr[i + 2] = arr[i]; } arr[0] = start;}// Function to rotate the arraypublic static void rotate(int[] arr){ left_rotate(arr); right_rotate(arr); for(int i = 0; i < arr.Length; i++) { Console.Write(arr[i] + " "); }}// Driver codepublic static void Main(){ int[] arr = { 1, 2, 3, 4, 5, 6 }; rotate(arr);}}// This code is contributed by chitranayal |
Javascript
<script> // Javascript program to implement // the above approach // function to left rotate function left_rotate(arr) { let last = arr[1]; for (let i = 3; i < 6; i = i + 2) { arr[i - 2] = arr[i]; } arr[6 - 1] = last; } // function to right rotate function right_rotate(arr) { let start = arr[6 - 2]; for (let i = 6- 4; i >= 0; i = i - 2) { arr[i + 2] = arr[i]; } arr[0] = start; } // Function to rotate the array function rotate(arr) { left_rotate(arr); right_rotate(arr); for (let i = 0; i < 6; i++) { document.write(arr[i] + " "); } } let arr = [ 1, 2, 3, 4, 5, 6 ]; rotate(arr); </script> |
Output:
5 4 1 6 3 2
Time Complexity: O(N)
Auxiliary Space: O(1)
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