Improving the Sum of Pairs solution on Codewars

Question

Improving the Sum of Pairs solution on Codewars

Seeking assistance in optimizing a solution for a problem that has already been identified. However, the existing code is not efficient when dealing with large arrays - view the problem on codeWars : Sum of Pairs

Below is the current code snippet:


var sum_pairs=function(e, sum){

var result=null;
var arrLen=e.length;
for(let i=0;i<arrLen-1;i++){
  let nextIndex=e.slice(i+1,arrLen).indexOf(sum-e[i]);
  if(nextIndex>=0){ 
    result=[e[i],e[nextIndex+1+i]];
    arrLen=nextIndex+1+i; 
  }
}
return result;
}

It's understood that this may not be the most optimal solution. The code passes test cases but fails when handling large arrays - see the Result On codewars

The goal is to improve this code and learn techniques for writing more efficient code.

javascript arrays algorithm memoization

Answer 1

Answer №1

To enhance efficiency, a possible approach involves utilizing the Set data structure to keep track of previously iterated numbers. This way, each element can be checked against existing sums with a complexity that remains constant for insertion and search operations, ultimately leading to a linear time and space algorithm.

const findSumPairs = function(numbers, target) {
  if (numbers.length < 2) return undefined; // Insufficient numbers for pair formation.
  let numSet = new Set()
  numSet.add(numbers[0]);
  for (let i = 1; i < numbers.length; ++i) {
    let complement = target - numbers[i];
    if (numSet.has(complement)) { // Check if the required number for pair completion has been encountered before.
      return [complement, numbers[i]];
    }
    numSet.add(numbers[i]); // If not, add the number to the set and continue.
  }
  return undefined; // No valid pairs found in the array.
}

Answer 2

To enhance efficiency, a possible approach involves utilizing the Set data structure to keep track of previously iterated numbers. This way, each element can be checked against existing sums with a complexity that remains constant for insertion and search operations, ultimately leading to a linear time and space algorithm.

const findSumPairs = function(numbers, target) {
  if (numbers.length < 2) return undefined; // Insufficient numbers for pair formation.
  let numSet = new Set()
  numSet.add(numbers[0]);
  for (let i = 1; i < numbers.length; ++i) {
    let complement = target - numbers[i];
    if (numSet.has(complement)) { // Check if the required number for pair completion has been encountered before.
      return [complement, numbers[i]];
    }
    numSet.add(numbers[i]); // If not, add the number to the set and continue.
  }
  return undefined; // No valid pairs found in the array.
}

Answer 3

Answer №2

function findPairOfSum (arr, target) {
 if (arr.length<2) return null
  let numSet = new Set()
  for (let j= 0;j<arr.length;j++){
    let difference = target - arr[j]
    if( numSet.has(difference)){
      return [difference,arr[j]]
    }
    numSet.add(arr[j])
  }
  return null
}

Answer 4

function findPairOfSum (arr, target) {
 if (arr.length<2) return null
  let numSet = new Set()
  for (let j= 0;j<arr.length;j++){
    let difference = target - arr[j]
    if( numSet.has(difference)){
      return [difference,arr[j]]
    }
    numSet.add(arr[j])
  }
  return null
}

Improving the Sum of Pairs solution on Codewars

Answer №1

Answer №2

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