// 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', 'a', '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
// // O(a + b)
// const containsCommonItems = (arr1, arr2) => {
// // Loop through first array and make an object
// // where the elements are properties
// let map = {};
// for (let i = 0; i < arr1.length; i++) {
// if(!map[arr1[i]]) {
// const item = arr1[i];
// map[item] = true;
// }
// }
// // console.log(map);
// // Loop through second array and see if
// // elements exist object properties
// for (let j = 0; j < arr2.length; j++) {
// if(map[arr2[j]]) {
// return true;
// }
// }
// return false;
// }
// const containsCommonItems2 = (arr1, arr2) => {
// return arr1.some(element => arr2.includes(element))
// }
// console.log(containsCommonItems(array1, array2));
// console.log(containsCommonItems2(array1, array2));
// Google Interview Example
// Naive
function hasPairWithSum(arr, sum){
var len = arr.length;
for(var i = 0; i<len-1; i++) {
for (var j = i+1; j<len; j++) {
if (arr[i] + arr[j] === sum)
return true;
}
}
return false;
}
// Better
function hasPairWithSum2(arr, sum) {
const mySet = new Set();
const len = arr.length;
for (let i = 0; i < len; i++) {
if (mySet.has(arr[i])) {
return true;
}
mySet.add(sum - arr[i]);
}
return false;
}
console.log(hasPairWithSum2([6,4,3,2,1,7], 9))
