0217 Contains Duplicate

Solved at: 230129

Question

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.

Solution

class Solution {
    func containsDuplicate(_ nums: [Int]) -> Bool {
        var set = Set<Int>()
        for num in nums {
            if set.contains(num) {
                return true
            }
            else {
                set.insert(num)
            }
        }
        return false
    }
}

Results

• Runtime 642 ms Beats 44.57%
• Memory 19 MB Beats 10.85%

Complexity Analysis

Both $O(N)$

Takeaways

Using sorting can sacrifice time to $O(N \log N)$ and pull down space into $O(1)$