A Gift Well Spent

A Gift Well SpentCodewars

Approach

Solve the problem

1. if the input array is empty return null

2. copy input array through 'slice(0)' and reducing for compare

   1. Find the index of the value that satisfies (x-acc) in the value of the right array, that is, an array of n+1 or greater. for that array.slice(i).indexOf(x - acc) + i

3. if there is no answer in process-2, will return last elements of array so if result.length is not equal 2 we didn't found result so should be return null, if result.length equals 2. return elements

Solution

JavaScript

const buy = (x, arr) => {
  if (!arr.length) {
    return null;
  }
  
  const result = arr.slice(0).reduce((acc, cur, i, array) => {
    if (array.slice(i).indexOf(x - acc) !== -1) {
      const indexes = [i - 1, array.slice(i).indexOf(x - acc) + i];
      array.splice(0);
      
      return indexes;
    }
    
    return cur;
  });
  
  return result.length === 2 ? result : null;
};