Check in binary array the number represented by a subarray is odd or even

Last Updated : 19 Sep, 2023

Given an array such that all its terms is either 0 or 1.You need to tell the number represented by a subarray a[l..r] is odd or even

Examples :

Input : arr = {1, 1, 0, 1}          l = 1, r = 3  Output : odd          number represented by arr[l...r] is           101 which 5 in decimal form which is           odd    Input :  arr = {1, 1, 1, 1}           l = 0, r = 3  Output : odd

The important point to note here is all the odd numbers in binary form have 1 as their rightmost bit and all even numbers have 0 as their rightmost bit.
The reason is simple all other bits other than the rightmost bit have even values and the sum of even numbers is always even. Now the rightmost bit can have a value of either 1 or 0 as we know even + odd = odd so when the rightmost bit is 1 the number is odd and when it is 0 the number is even.
So to solve this problem we have to just check if a[r] is 0 or 1 and accordingly print odd or even

Implementation:

C++

// C++ program to find if a subarray // is even or odd. #include<bits/stdc++.h> using namespace std;  // prints if subarray is even or odd void checkEVENodd (int arr[], int n, int l, int r) {     // if arr[r] = 1 print odd     if (arr[r] == 1)         cout << "odd" << endl;      // if arr[r] = 0 print even     else         cout << "even" << endl; }  // driver code int main() {     int arr[] = {1, 1, 0, 1};     int n = sizeof(arr)/sizeof(arr[0]);     checkEVENodd (arr, n, 1, 3);     return 0; }

Java

// java program to find if a subarray // is even or odd. import java.io.*;  class GFG  {     // prints if subarray is even or odd     static void checkEVENodd (int arr[], int n, int l, int r)     {         // if arr[r] = 1 print odd         if (arr[r] == 1)             System.out.println( "odd") ;              // if arr[r] = 0 print even         else             System.out.println ( "even") ;     }      // driver code     public static void main (String[] args)      {         int arr[] = {1, 1, 0, 1};         int n = arr.length;         checkEVENodd (arr, n, 1, 3);                       } }  // This article is contributed by vt_m.

Python3

# Python3 program to find if a  # subarray is even or odd.  # Prints if subarray is even or odd def checkEVENodd (arr, n, l, r):      # if arr[r] = 1 print odd     if (arr[r] == 1):         print("odd")      # if arr[r] = 0 print even     else:         print("even")  # Driver code arr = [1, 1, 0, 1] n = len(arr) checkEVENodd (arr, n, 1, 3)  # This code is contributed by Anant Agarwal.

// C# program to find if a subarray // is even or odd. using System;   class GFG {          // prints if subarray is even or odd     static void checkEVENodd (int []arr,                       int n, int l, int r)     {                  // if arr[r] = 1 print odd         if (arr[r] == 1)             Console.WriteLine( "odd") ;               // if arr[r] = 0 print even         else             Console.WriteLine( "even") ;     }       // driver code     public static void Main()      {                  int []arr = {1, 1, 0, 1};         int n = arr.Length;                  checkEVENodd (arr, n, 1, 3);     } }   // This article is contributed by Anant Agarwal.

PHP

<?php // PHP program to find if a subarray // is even or odd.  // prints if subarray is even or odd function checkEVENodd ($arr, $n, $l, $r) {     // if arr[r] = 1 print odd     if ($arr[$r] == 1)         echo "odd", "\n";      // if arr[r] = 0 print even     else         echo "even", "\n"; }  // Driver code $arr = array(1, 1, 0, 1); $n = sizeof($arr); checkEVENodd ($arr, $n, 1, 3);  // This code is Contributed by Ajit ?>

JavaScript

<script>      // Javascript program to find      // if a subarray is even or odd.          // prints if subarray is even or odd     function checkEVENodd (arr, n, l, r)     {                    // if arr[r] = 1 print odd         if (arr[r] == 1)             document.write("odd") ;                 // if arr[r] = 0 print even         else             document.write("even") ;     }          let arr = [1, 1, 0, 1];     let n = arr.length;      checkEVENodd (arr, n, 1, 3);  </script>

Output

odd

Time Complexity : O(1)
Space Complexity : O(1)

This article is contributed by Ayush Jha.

GCDs of given index ranges in an Array

Ayush Jha

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Check in binary array the number represented by a subarray is odd or even

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