BitwiseOR_subArraySum.cpp

// The integer array arr[] is given and print the resultant value of the bitwise OR
// of the sum of all the possible sub-arrays of the given array arr[].

// Note: A sub-array is a sequence of array-elements that could be drawn from other
//       sequence of array-elements by removing zero or more elements without changing 
//       the order of the remaining elements.



// Input Format
// -------------
// Line-1: Read the size of array P.
// Line-2: Read the array elements(space separated values).

// Output Format
// --------------
// Print the resultant value.


// Sample input-1:
// ---------------
// 4
// 0 2 1 3
// Sample output-1:
// ----------------
// 7

// Explanation
// The sums of sub-arrays are
// 0 1 2 3 4 5 6. 
// and bitwise OR operation
// 0 OR 1 OR 2 OR 3 OR 4 OR 5 OR 6 = 7.



// Sample input-2:
// ---------------
// 4
// 0 0 0 0
// Sample output-2:
// ----------------
// 0

// Explanation
// Only one sum sub-arrays i.e. 0.



#include<bits/stdc++.h>
using namespace std;
vector<int> res;
void solve(vector<int> &nums,int &sum,int ind){
    if(ind==nums.size()){
        res.push_back(sum);
        return;
    }
    for(int i=ind;i<nums.size();i++){
        sum=sum+nums[i];
        solve(nums,sum,ind+1);
        ind=ind+1;
        sum=sum-nums[i];
    }
}
int main(){
    int n;
    cin>>n;
    vector<int> nums(n,0);
    for(int i=0;i<nums.size();i++){
        cin>>nums[i];
    }
    int sum=0;
    solve(nums,sum,0);
    int x=res[0];
    for(int i=1;i<res.size();i++){
        x=x|res[i];
    }
    cout<<x;
}