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Leetcode
Easy
Arrays
Hash Maps
Sets
Contains Duplicate
Determine whether any value appears at least twice in an array.
Acceptance 73%
Problem Statement
Given an integer array, decide whether the array contains any duplicate value. Return true if at least one number appears more than once; otherwise return false.
A good solution should be able to process the list efficiently by tracking what has already been seen.
Input Format
- An integer array
nums. - Each element may appear zero or more times.
Output Format
- Return
trueif any value occurs at least twice. - Return
falseif all values are distinct.
Constraints
- The array may be empty.
- Values can be negative, zero, or positive.
- Aim for better than time if possible.
Examples
Sample cases returned by the problem API.
Example 1
Input
nums = [1,2,3,1]
Output
true
Explanation
The value 1 appears twice.
Example 2
Input
nums = [1,2,3,4]
Output
false
Explanation
All values are distinct.
Show 1 more example
Example 3
Input
nums = [1,1,1,3,3,4,3,2,4,2]
Output
true
Explanation
Several values repeat, so the answer is true.
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