GoogleInterview.js

// Given 2 arrays, create a function that let's a user know (true/false) whether these two arrays contain any common items
//For Example:
//const array1 = ['a', 'b', 'c', 'x'];//const array2 = ['z', 'y', 'i'];
//should return false.
//-----------
//const array1 = ['a', 'b', 'c', 'x'];//const array2 = ['z', 'y', 'x'];
//should return true.

// 2 parameters - arrays - no size limit
// return true or false

function containsCommonItem(arr1, arr2) {
    for (let i=0; i < arr1.length; i++) {
      for ( let j=0; j < arr2.length; j++) {
        if(arr1[i] === arr2[j]) {
          return true;
        }
      }
    }
    return false
  }
  
  //O(a*b)
  //O(1) - Space Complexity
  
  const array1 = ['a', 'b', 'c', 'x'];
  const array2 = ['z', 'y', 'a'];
  
  function containsCommonItem2(arr1, arr2) {
    // loop through first array and create object where properties === items in the array
    // can we assume always 2 params?
  
    let map = {};
    for (let i=0; i < arr1.length; i++) {
      if(!map[arr1[i]]) {
        const item = arr1[i];
        map[item] = true;
      }
    }
    // loop through second array and check if item in second array exists on created object. 
    for (let j=0; j < arr2.length; j++) {
      if (map[arr2[j]]) {
        return true;
      }
    }
    return false
  }
  
  //O(a + b) Time Complexity
  //O(a) Space Complexity
  
  // containsCommonItem2(array1, array2)
  
  function containsCommonItem3(arr1, arr2) {
    return arr1.some(item => arr2.includes(item))
  }
  
  containsCommonItem(array1, array2)
  containsCommonItem2(array1, array2)
  containsCommonItem3(array1, array2)