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Are there duplicates (Bonus)

implement a function called, areThereDuplicates which accepts a variable number of arguments, and checks whether there are any duplicates among the arguments passed in. You can solve this using the frequency counter pattern OR the multiple pointers pattern.

Example 1​

Input: nums = 1,2,3
Output: false

Example 2​

Input: nums = 1,2,2
Output: true

Example 2​

Input: nums = 'a' , 'b' , 'c' , 'a'
Output: true

Solution​

areThereDuplicates (hashmap)
/**
 * @param {number} num1
 * @param {number} num2
 * @param {number} num3
 * @param {number} num4
 * @return {boolean}
 */

function areThereDuplicates(num1, num2, num3, num4) {
  // good luck. (supply any arguments you deem necessary.)
  const arr = [num1, num2, num3, num4];
  const map = new Map();
  for (let i = 0; i < arr.length; i++) {
    const count = map.get(arr[i]);
    if (count) {
      map.set(arr[i], count + 1);
    } else {
      map.set(arr[i], 1);
    }
  }
  for (const num of map.keys()) {
    if (map.get(num) > 1) {
      return true;
    }
  }
  return false;
}
areThereDuplicates (Multiple Pointers)
function areThereDuplicates(...args) {
  // Two pointers
  args.sort((a, b) => a > b);
  let start = 0;
  let next = 1;
  while (next < args.length) {
    if (args[start] === args[next]) {
      return true;
    }
    start++;
    next++;
  }
  return false;
}
areThereDuplicates (javascript set)
function areThereDuplicates(arg) {
  return new Set(arg).size !== arg.length;
}