217 - Contains Duplicate

217. Contains Duplicate

Problem Statement

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

Example 2:

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

Example 3:

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

 

Constraints:

• 1 <= nums.length <= 105
• -109 <= nums[i] <= 109

Solutions

Rust

impl Solution {
    pub fn contains_duplicate(nums: Vec<i32>) -> bool {
        let mut set = std::collections::HashSet::new();

        for num in nums {
            if set.contains(num) {
                return true;
            } else {
                set.insert(num);
            }
        }
        false
    }
}

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