King-pin-Challenge.js

// 1. Given an array arr and a number N, find a pair (x,y) such that x+y=N. Return null if it doesn’t exist.

// 2. Find the sum of continuous subarray within a one-dimensional array of numbers that has the largest sum.


// 1....

function isPairInArray(arr, n) {
  for (let i=0;i < arr.length; i++) {
    for (let j=1; j < arr.length; j++) {
      if (arr[i] + arr[j] === n && i !== j) {
        return [arr[i], arr[j]]
      }
    }
  }
  return null;
}

// 1....
function sumOfContinuousSubarray(arr)
{
  let max = -Infinity
  let maxEnd = 0
  for (let sub of arr)
  {
    maxEnd = maxEnd + sub;
    if (max < maxEnd){
      max = maxEnd
    }
    if (maxEnd < 0){
      maxEnd = 0
    }
  }
  return max
}

// use this to test your cases
function testCases(result, expected) {
  if (JSON.stringify(result) === JSON.stringify(expected)) {
    console.log({ result, expected}, 'PASSED')
    return
  }
  console.log({ result, expected}, 'FAILED')
}

// Test cases For

/**
 1. Given an array arr and a number N, find a pair (x,y) such that x+y=N. Return null if it doesn’t exist.
 **/

let arr = [1, 8, 30, 40, 100, 20];
let n = 60;
let n1 = 70;
let n2 = 140;
// SHOULD pass [40,20]
testCases(isPairInArray(arr, n), [40,20])

// SHOULD pass [30,40]
testCases(isPairInArray(arr, n1), [30,40])

// SHOULD pass [40,100]
testCases(isPairInArray(arr, n2), [40, 100])

/**
 2. Find the sum of continuous subarray within a one-dimensional array of numbers that has the largest sum.
 **/
const a = [ -2, -1, 1, -1, -2, 1, 5, -3 ]
const b = [ -2, -3, 4, -1, -2, 1, 5, -3 ]
const c = [ -2, -3, 4, -6, -2, 1, 9, -3 ]

// SHOULD pass  6
testCases(sumOfContinuousSubarray(a), 6)

// SHOULD pass  7
testCases(sumOfContinuousSubarray(b), 7)

// SHOULD pass  10
testCases(sumOfContinuousSubarray(c), 10)