Longest Subarray With Sum K

Easy

0/40

Average time to solve is 20m

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375 upvotes

Problem statement

You are given an array 'a' of size 'n' and an integer 'k'.

Find the length of the longest subarray of 'a' whose sum is equal to 'k'.

Example :

Input: ‘n’ = 7 ‘k’ = 3
‘a’ = [1, 2, 3, 1, 1, 1, 1]

Output: 3

Explanation: Subarrays whose sum = ‘3’ are:

[1, 2], [3], [1, 1, 1] and [1, 1, 1]

Here, the length of the longest subarray is 3, which is our final answer.

Detailed explanation ( Input/output format, Notes, Images )

Input Format :

The first line contains two integers, ‘n’ and ‘k’, denoting the size of array ‘a’ and the integer ‘k’.

The following line contains ‘n’ integers, denoting the array ‘a’.

Output format :

Print the length of the longest subarray whose sum is equal to ‘k’.

Note :

You do not need to print anything; it has already been taken care of. Just implement the given function.

Sample Input 1 :

7 3
1 2 3 1 1 1 1

Sample Output 1 :

Explanation Of Sample Input 1 :

Subarrays whose sum = ‘3’ are:
[1, 2], [3], [1, 1, 1] and [1, 1, 1]
Here, the length of the longest subarray is 3, which is our final answer.

Sample Input 2 :

4 2
1 2 1 3

Sample Output 2 :

Sample Input 3 :

5 2
2 2 4 1 2

Sample Output 3 :

Expected time complexity :

The expected time complexity is O(n).

Constraints :

1 <= 'n' <= 5 * 10 ^ 6
1 <= 'k' <= 10^18
0 <= 'a[i]' <= 10 ^ 9

Time Limit: 1-second

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