# Find bitwise AND (&) of all possible sub-arrays

Given an array A of size N where, . The task is to find the AND of all possible sub-arrays of A and then the AND of all these results.

Examples:

Input : 1 2 3
Output : 0
All possible subarrays are
{1}, {2}, {3}, {1, 2}, {2, 3} and {1, 2, 3}
ANDs of these subarrays are 1, 2, 3, 0, 2, 0.
AND of these ANDs is 0.

Input : 100 500 1000
Output : 96


## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:
The Naive solution is to find the AND of all the sub-arrays and then print the AND of their results. This will lead to O(N2) solution.

Optimal Solution: Using the property that i:e it doesn’t matter how many times an element comes, it’s ANDing will be counted as one only. Thus our problem reduces to finding the AND of all the elements of the array only.
Below is the implementation of above approach.

## C++

 // C++ program to find of all the sub-arrays  #include  using namespace std;     // function to return AND of sub-arrays  int AND(int a[], int n)  {      int ans = a;      for (int i = 0; i < n; ++i)           ans &= a[i];        return ans;  }     // Driver program  int main()  {      int a[] = { 1, 2, 3 };         // size of the array      int n = sizeof(a) / sizeof(a);         // print and of all subarrays      cout << AND(a, n);         return 0;  }

## Java

 //Java program to find of all the sub-arrays  public class GFG {         //function to return AND of sub-arrays      static int AND(int a[], int n)      {       int ans = a;       for (int i = 0; i < n; ++i)            ans &= a[i];         return ans;      }         // Driver code      public static void main(String[] args) {                 int a[] = { 1, 2, 3 };              // size of the array           int n = a.length;              // print and of all subarrays           System.out.println(AND(a, n));      }  }

## Python 3

 # Python 3 Program  to find of all the sub-arrays      # function to return AND of sub-arrays  def AND(a, n) :         ans = a      for i in range(n) :          ans &= a[i]                 return ans           # Driver Code  if __name__ == "__main__" :         a = [ 1, 2, 3]         # size of the array      n = len(a)         # print and of all subarrays      print(AND(a, n))     # This code is contributed by ANKITRAI1

## C#

 //C# program to find of all the sub-arrays       using System;     public class GFG {            //function to return AND of sub-arrays       static int AND(int []a, int n)       {        int ans = a;        for (int i = 0; i < n; ++i)             ans &= a[i];          return ans;       }            // Driver code       public static void Main() {                    int []a = { 1, 2, 3 };                 // size of the array            int n = a.Length;                 // print and of all subarrays            Console.WriteLine(AND(a, n));       }   }

## PHP

 

OUTPUT:

0


Time Complexity: O(N)

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