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🔥Contains Duplicate: Set Collision DetectorEasy
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EasyArrays & Hashing•Acceptance: 61.3%

Contains Duplicate: Set Collision Detector

Targeted in FAANG & Tech OA:AmazonAppleAdobeSwiggy
Real-World Engineering Context
Primary deduplication routine in distributed message queues (Kafka, AWS SQS) and unique user identifier validations in PostgreSQL.
Given an integer array `nums`, return `true` if any value appears at least twice in the array, and return `false` if every element is distinct.

Sample Test Cases

Input: [[1,2,3,1]]
Expected: true
Input: [[1,2,3,4]]
Expected: false
Input: [[1,1,1,3,3,4,3,2,4,2]]
Expected: true

Constraints

  • 1 <= nums.length <= 10^5
  • -10^9 <= nums[i] <= 10^9
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