Print pair with maximum AND value in an array
Given an array of n positive elements, find the maximum AND value and the pair of elements generating the maximum AND value from the array.
AND is bitwise & operator.
Examples:
Input : arr[] = {4, 8, 12, 16} Output : Pair = 8, 12 Maximum AND value = 8 Input : arr[] = {4, 8, 16, 2} Output : Pair = Not Possible Maximum AND value = 0
Approach:
Finding Maximum AND value is same as Maximum AND value in an array. Our task is to find the pair of elements resulting in obtained AND value. For finding the elements, simply traverse the whole array and find the AND value of each element with the obtained maximum AND value (result) and if arr[i] & result == result , that means arr[i] is the element which will generate maximum AND value. Also, in the case if maximum AND value (result) is zero then we should print “Not possible” in that case.
Below is the implementation of above approach:
C++
// CPP Program to find pair with // maximum AND value #include <bits/stdc++.h> using namespace std; // Utility function to check number of // elements having set msb as of pattern int checkBit( int pattern, int arr[], int n) { int count = 0; for ( int i = 0; i < n; i++) if ((pattern & arr[i]) == pattern) count++; return count; } // Function for finding maximum and // value pair int maxAND( int arr[], int n) { int res = 0, count; // iterate over total of 30bits // from msb to lsb for ( int bit = 31; bit >= 0; bit--) { // find the count of element // having set msb count = checkBit(res | (1 << bit), arr, n); // if count >= 2 set particular // bit in result if (count >= 2) res |= (1 << bit); } // Find the elements if (res == 0) cout << "Not Possible\n" ; else { // print the pair of elements cout << "Pair = " ; count = 0; for ( int i = 0; i < n && count < 2; i++) { // inc count value after // printing element if ((arr[i] & res) == res) { count++; cout << arr[i] << " " ; } } } // return the result value return res; } // Driver function int main() { int arr[] = { 4, 8, 6, 2 }; int n = sizeof (arr) / sizeof (arr[0]); cout << "\nMaximum AND Value = " << maxAND(arr, n); return 0; } |
Java
// Java Program to find pair // with maximum AND value import java.util.*; import java.io.*; class GFG { // Utility function to check number of // elements having set msb as of pattern static int checkBit( int pattern, int arr[], int n) { int count = 0 ; for ( int i = 0 ; i < n; i++) if ((pattern & arr[i]) == pattern) count++; return count; } // Function for finding maximum and // value pair static int maxAND( int arr[], int n) { int res = 0 , count; // iterate over total of 30bits // from msb to lsb for ( int bit = 31 ; bit >= 0 ; bit--) { // find the count of element // having set msb count = checkBit(res | ( 1 << bit), arr, n); // if count >= 2 set particular // bit in result if (count >= 2 ) res |= ( 1 << bit); } // Find the elements if (res == 0 ) System.out.println( "Not Possible" ); else { // print the pair of elements System.out.print( "Pair = " ); count = 0 ; for ( int i = 0 ; i < n && count < 2 ; i++) { // inc count value after // printing element if ((arr[i] & res) == res) { count++; System.out.print(arr[i] + " " ); } } System.out.println(); } // return the result value return res; } // Driver code public static void main(String args[]) { int arr[] = { 4 , 8 , 6 , 2 }; int n = arr.length; System.out.println( "Maximum AND Value = " + maxAND(arr, n)); } } // This code is contributed by Sahil_Bansall |
Python3
# Python 3 Program to find pair with # maximum AND value # Utility function to check number of # elements having set msb as of pattern def checkBit(pattern, arr, n): count = 0 for i in range ( 0 , n): if ((pattern & arr[i]) = = pattern): count + = 1 return count # Function for finding maximum and # value pair def maxAND(arr, n): res = 0 # iterate over total of 30bits # from msb to lsb for bit in range ( 31 , - 1 , - 1 ) : # find the count of element # having set msb count = checkBit(res | ( 1 << bit), arr, n) # if count >= 2 set particular # bit in result if (count > = 2 ): res | = ( 1 << bit) # Find the elements if (res = = 0 ): print ( "Not Possible" ) else : # print the pair of elements print ( "Pair = " , end = "") count = 0 i = 0 while (i < n and count < 2 ): # inc count value after # printing element if ((arr[i] & res) = = res) : count + = 1 print (arr[i] , end = " " ) i + = 1 # return the result value return res # Driver function arr = [ 4 , 8 , 6 , 2 ] n = len (arr) print ( "\nMaximum AND Value = " , maxAND(arr, n)) # This code is contributed by Smitha |
C#
// C# Program to find pair // with maximum AND value using System; class GFG { // Utility function to check number of // elements having set msb as of pattern static int checkBit( int pattern, int []arr, int n) { int count = 0; for ( int i = 0; i < n; i++) if ((pattern & arr[i]) == pattern) count++; return count; } // Function for finding maximum and // value pair static int maxAND( int []arr, int n) { int res = 0, count; // iterate over total of 30bits // from msb to lsb for ( int bit = 31; bit >= 0; bit--) { // find the count of element // having set msb count = checkBit(res | (1 << bit), arr, n); // if count >= 2 set particular // bit in result if (count >= 2) res |= (1 << bit); } // Find the elements if (res == 0) Console.Write( "Not Possible" ); else { // print the pair of elements Console.Write( "Pair = " ); count = 0; for ( int i = 0; i < n && count < 2; i++) { // inc count value after // printing element if ((arr[i] & res) == res) { count++; Console.Write(arr[i] + " " ); } } Console.WriteLine(); } // return the result value return res; } // Driver code public static void Main() { int []arr = { 4, 8, 6, 2 }; int n = arr.Length; Console.WriteLine( "Maximum AND Value = " + maxAND(arr, n)); } } // This code is contributed by vt_m |
PHP
<?php // php Program to find pair with // maximum AND value // Utility function to check number of // elements having set msb as of pattern function checkBit( $pattern , $arr , $n ) { $count = 0; for ( $i = 0; $i < $n ; $i ++) if (( $pattern & $arr [ $i ]) == $pattern ) $count ++; return $count ; } // Function for finding maximum // and value pair function maxAND( $arr , $n ) { $res = 0; // iterate over total of 30bits // from msb to lsb for ( $bit = 31; $bit >= 0; $bit --) { // find the count of element // having set msb $count = checkBit( $res | (1 << $bit ), $arr , $n ); // if count >= 2 set particular // bit in result if ( $count >= 2) $res |= (1 << $bit ); } // Find the elements if ( $res == 0) echo "Not Possible\n" ; else { // print the pair of elements echo "Pair = " ; $count = 0; for ( $i = 0; $i < $n && $count < 2; $i ++) { // inc count value after // printing element if (( $arr [ $i ] & $res ) == $res ) { $count ++; echo $arr [ $i ]. " " ; } } } // return the result value return $res ; } // Driver code $arr = array ( 4, 8, 6, 2 ); $n = sizeof( $arr ) / sizeof( $arr [0]); echo "\nMaximum AND Value = " .maxAND( $arr , $n ); //This code is contributed by mits ?> |
Javascript
<script> // Javascript program to find pair // with maximum AND value // Utility function to check number of // elements having set msb as of pattern function checkBit(pattern, arr, n) { let count = 0; for (let i = 0; i < n; i++) if ((pattern & arr[i]) == pattern) count++; return count; } // Function for finding maximum and // value pair function maxAND(arr, n) { let res = 0, count; // iterate over total of 30bits // from msb to lsb for (let bit = 31; bit >= 0; bit--) { // find the count of element // having set msb count = checkBit(res | (1 << bit), arr, n); // if count >= 2 set particular // bit in result if (count >= 2) res |= (1 << bit); } // Find the elements if (res == 0) System.out.prletln( "Not Possible" ); else { // print the pair of elements document.write( "Pair = " ); count = 0; for (let i = 0; i < n && count < 2; i++) { // inc count value after // printing element if ((arr[i] & res) == res) { count++; document.write(arr[i] + " " ); } } document.write( "<br/>" ); } // return the result value return res; } // Driver code let arr = [ 4, 8, 6, 2 ]; let n = arr.length; document.write( "Maximum AND Value = " + maxAND(arr, n)); </script> |
Output:
Pair = 4 6 Maximum AND value = 4
Time Complexity: O(n)
Auxiliary Space: O(n)