LeetCode Data Structure I: Day 1 - 001

containsDuplicate.js

// 217. 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.

const containsDuplicate = (nums) => {
  //     create an empty dictionary
  //     iterate through the array
  //     for each integer in the array check if the integer position exists in the dictionary
  //     if 'yes' return 'true'
  //     else add the integer's position to the dict and intialize it with a value of 1
  //     after the loop return false
  const dict = [];
  for (let num of nums) {
    if (dict[num]) return true;
    dict[num] = 1;
  }
  return false;
};

// Time: O(n)
// Space: O(1)

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]));