LC 217 Contains Duplicate

Implementation

// 217. 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. 

// 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 <= 105
// -109 <= nums[i] <= 109

// const containsDuplicate = (nums) => {
//     return new Set([...nums]).size !== nums.length
// };

// optimize solution
const containsDuplicate = (nums) => {
    const s = new Set();
    for(let num of nums){
        if(s.has(num)) return true;
        s.add(num);
    }
    return false;
};

console.log(containsDuplicate([1,2,3,1]))
console.log(containsDuplicate([1,2,3,4]))
console.log(containsDuplicate([1,1,1,3,3,4,3,2,4,2]))

Tests

// Test stub for 01.217.ContainsDuplicate

describe('01.217.ContainsDuplicate', () => {
  it('should have a test stub', () => {
    expect(true).toBe(true);
  });
});