217-contains-duplicate

217. Contains Duplicate (Easy) (https://leetcode.com/problems/contains-duplicate/)

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. Constraints: 1 <= nums.length <= 10^5 -10^9 <= nums[i] <= 10

function containsDuplicate(nums: number[]): boolean {
    const st = new Set<number>()
    for (const num of nums) {
        if (st.has(num)) {
            return true
        }
        st.add(num)
    }
    return false
}
 
// Local check:
console.log(containsDuplicate([1, 2, 3, 1])) // true
console.log(containsDuplicate([1, 2, 3, 4])) // false
console.log(containsDuplicate([1, 1, 1, 3, 3, 4, 3, 2, 4, 2])) // true

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

array 268 — то же set-семейство 645 — то же set-семейство leetcode