two-sum.ts

// given sorted array of numbers, find pair that sums to the target OR is closest to the target number

function findPair(a: number[], target: number): number[][]{
  let start = 0;
  let end = a.length - 1
  let result: number[][] = []
  // if we have two values that are at the same distance from the target, 
  // then array will contain both values, else it will only contain value that is nearer
  let nearByValues: number[][] = []
  let diff = Number.MAX_SAFE_INTEGER

  while(start < end){
    let startVal = a[start]
    let endVal = a[end]
    let sum = startVal + endVal
    if(sum === target){
      result.push([startVal, endVal])
      start++;
      end--;
    }else if(sum > target){
      end--
    }else {
      start++
    }
    let currentMin = Math.min(Math.abs(target - sum), diff)
    if(currentMin < diff){
      nearByValues.length = 0;
      nearByValues.push([startVal, endVal])
      diff = currentMin
    }else if(currentMin === diff){
      nearByValues.push([startVal, endVal])
    }
  }
  return result.length === 0 ? nearByValues : result;
}

console.log(findPair([2,4,5,6,7,9], 10))
console.log(findPair([2,4,7,9,11], 10))