Contains Duplicate

Easy

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.

Examples

Input	Output
nums = [1,2,3,1]	true
nums = [1,2,3,4]	false

Python Solution

def contains_duplicate(nums: list[int]) -> bool:
    return len(nums) != len(set(nums))

JavaScript Solution

function containsDuplicate(nums) {
  return new Set(nums).size !== nums.length;
}

Step-by-Step Explanation

A set contains only unique elements. If len(set) < len(nums), there are duplicates.

Complexity Analysis

Time	O(n)
Space	O(n)

Tags

ArrayHash Map

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