Hacker rank AND xor OR

#1


I am not able to solve this.please help

#2

The idea is that if you have a value b in your stack, and you encounter a value c which is smaller, then b cannot form a minimum pair with anything to the right of c. So once you yield the pair (b,c) you can safely dispose of b (you already handled possible pairs to the left).

-> For e.g. A=[4,5,3,7] yields => (i,top): (5,4);(3,5);(3,4);(7,3), which are the only contiguous pairs of two smallest elements. Note, for example, (4,7) is impossible, because that includes all of A => (3,4). [see below] New smaller elements pop out earlier (contiguously) elements, such as 3 popping 5 and 4.
-> Loop through A linearly.
-> When to push and pop to the stack? Push to the stack each new element in A, i, and if i is smaller than stack top, keep popping until all bigger earlier values popped (or stack empty) before adding i. This way any new smaller element pops all previous bigger elements, and the stack keeps pushing new elements when empty - always having a new pair (at least one element in non-empty stack and new element i).

simplify the boolean function (^ is for XOR):

(((A B) ^ (A + B)) (A ^ B)) =           
apply A ^ B = (A'B) + (A B')
( ((A B)' (A + B)) + ((A B) (A + B)')) (A ^ B)) =   
apply DeMorgan law (X+Y+...)'=X'Y'Z'... and (XYZ...)'=X'+Y'+...
( ((A' + B') (A + B)) + ((A B) (A' B'))) (A ^ B)) = 
apply Distributive Law X(Y+Z) = XY + XZ
(A'A + A'B + AB' + BB' + AA' + BB') (A ^ B) =       
apply X+X=X, XX=X
(A'B + AB') (A ^ B) =
(A ^ B) (A ^ B) = A ^ B = A xor B
Solution :


#include<iostream>
#include<stack>
#include<vector>
using namespace std;
int main()
{	vector <long int> v;
	stack <long int> s;
	long int temp,i,n;
	long long max_xor=0,min_xor;
	cin>>n;
	for(i=0;i<n;i++)
	{
		cin>>temp;
		v.push_back(temp);
	}
	for(i=0;i<n;i++)
	{
		while(!s.empty())
		{
			min_xor=v[i]^s.top();
			if(min_xor>max_xor)
			max_xor=min_xor;
			if(v[i]<s.top())
			s.pop();
			else
			break;
		}
		s.push(v[i]);
	}
	cout<<max_xor<<endl;
}
#3

image
image1280×936 192 KB

Please can you help me in finding the the subsets generated from that array

#4

You want to generate the subset from array [1,3,5,7,8] cause subset won’t be required to solve this question.

#5

No,my question is not related to this .It was related to some other question w

#6

my question is bascically to find all subsets of size 2 in an array

#8

For the mentioned array, answer would be
1 3
1 5
1 7
1 8
3 5
3 7
3 8
5 7
5 8
7 8

#9

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