Leaderboard
Showing:
Handle Score
@Ibrahim Nash 5725
@blackshadows 5685
@akhayrutdinov 5111
@mb1973 4989
@Quandray 4908
@saiujwal13083 4156
@sanjay05 3762
@marius_valentin_dragoi 3511
@sushant_a 3453
@KshamaGupta 3318
@the_coder95 3302
Complete Leaderboard
Find sum of different corresponding bits for all pairs
Hard Accuracy: 17.4% Submissions: 444 Points: 8

We define f (X, Y) as number of different corresponding bits in binary representation of X and Y. For example, f (2, 7) = 2, since binary representation of 2 and 7 are 010 and 111, respectively. The first and the third bit differ, so f (2, 7) = 2.

You are given an array A of N integers, A1, A2 ,…, AN. Find sum of f(Ai, Aj) for all pairs (i, j) such that 1 ≤ i, j ≤ N. Return the answer modulo 109+7.

Example 1:

Input: N = 2
A = {2, 4}
Output: 4
Explaintion: We return 
f(2, 2) + f(2, 4) + 
f(4, 2) + f(4, 4) = 
0 + 2 + 
2 + 0 = 4.

Example 2:

Input: N = 3
A = {1, 3, 5}
Output: 8
Explaination: We return 
f(1, 1) + f(1, 3) + f(1, 5) + 
f(3, 1) + f(3, 3) + f(3, 5) + 
f(5, 1) + f(5, 3) + f(5, 5) = 
0 + 1 + 1 + 
1 + 0 + 2 + 
1 + 2 + 0 = 8.

Your Task:
You do not need to read input or print anything. Your task is to complete the function countBits() which takes the value N and the array A as input parameters and returns the desired count modulo 109+7.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)

Constraints:
1 ≤ N ≤ 104
-2,147,483,648 ≤ A[i] ≤ 2,147,483,647

to report an issue on this page.

Editorial

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes

All Submissions

My Submissions:

Login to access your submissions.

Find sum of different corresponding bits for all pairs

Output Window