Leaderboard
Showing:
Handle Score
@Ibrahim Nash 6420
@blackshadows 6376
@mb1973 5604
@Quandray 5231
@akhayrutdinov 5111
@saiujwal13083 4510
@sanjay05 3762
@kirtidee18 3673
@marius_valentin_dragoi 3522
@sushant_a 3459
@verma_ji 3413
Complete Leaderboard
Count pairs with given sum
Easy Accuracy: 41.59% Submissions: 29181 Points: 2

Given an array of N integers, and an integer K, find the number of pairs of elements in the array whose sum is equal to K.


Example 1:

Input:
N = 4, K = 6
arr[] = {1, 5, 7, 1}
Output: 2
Explanation: 
arr[0] + arr[1] = 1 + 5 = 6 
and arr[1] + arr[3] = 5 + 1 = 6.


Example 2:

Input:
N = 4, X = 2
arr[] = {1, 1, 1, 1}
Output: 6
Explanation: 
Each 1 will produce sum 2 with any 1.


Your Task:
You don't need to read input or print anything. Your task is to complete the function getPairsCount() which takes arr[], n and as input parameters and returns the number of pairs that have sum K.


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

Constraints:
1 <= N <= 105
1 <= K <= 108
1 <= Arr[i] <= 106

 

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.

Count pairs with given sum

Output Window