find pair of numbers in array that add to given sum

Question

Question: Given an unsorted array of positive integers, is it possible to find a pair of integers from that array that sum up to a given sum?

Constraints: This shou

Answer 1

First you should find reverse array => sum minus actual array then check whether any element from these new array exist in the actual array.

const arr = [0, 1, 2, 6];

const sum = 8;

let isPairExist = arr
  .map(item => sum - item) // [8, 7, 6, 2];
  .find((item, index) => {
    arr.splice(0, 1); // an element should pair with another element
    return arr.find(x => x === item);
  })
  ? true : false;

console.log(isPairExist);