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🔥Subarray Sum Equals K: Prefix Sum Hash FrequencyMedium
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MediumArrays & Hashing•Acceptance: 43.5%

Subarray Sum Equals K: Prefix Sum Hash Frequency

Targeted in FAANG & Tech OA:GoogleMetaSwiggy
Real-World Engineering Context
Critical in financial audit reconciliations at Stripe and Razorpay to detect exact matched billing transaction sequences in ledger histories.
Given an array of integers `nums` and an integer `k`, return the total number of continuous subarrays whose sum equals to `k`.

Sample Test Cases

Input: [[1,1,1],2]
Expected: 2
Input: [[1,2,3],3]
Expected: 2
Input: [[1,-1,0],0]
Expected: 3

Constraints

  • 1 <= nums.length <= 2 * 10^4
  • -1000 <= nums[i] <= 1000
  • -10^7 <= k <= 10^7
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