Files
cpp-flashcards/org/study_deck_02/dsa/arrays-hashing/0217-contains-duplicate.org
T
tomatocream 1dec88aaf2 feat: populate note files with problem descriptions and code stubs
Add populate-notes.mjs that fetches problem descriptions and
Python/C++ code stubs from LeetCode's GraphQL API. Populated
all 197 NeetCode 150 note files with:
- Problem description (examples, constraints)
- Python code stub (function signature)
- C++ code stub (function signature + includes)

API responses cached in leetcode/.cache/leetcode/ for instant re-runs.
2026-06-01 17:22:07 +08:00

989 B

TODO 0217. 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.

Example 1:

Input: nums = [1,2,3,1]

Output: true

Explanation:

The element 1 occurs at the indices 0 and 3.

Example 2:

Input: nums = [1,2,3,4]

Output: false

Explanation:

All elements are distinct.

Example 3:

Input: nums = [1,1,1,3,3,4,3,2,4,2]

Output: true

Constraints:

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

TODO Approach

Write your approach here.

TODO Python

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:

TODO C++

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        
    }
};