```\n# Write a function that returns the indices of an array Arr for\n# elements that add up to a given number K\n# For example:\n# Given an array: [1,1,2,23,4,9,13,6,9] and K = 10, returns [[0,8],[1,5]\n```\nat first it looked easy to use either hashtable to store indices but there are duplicates, array is not sorted therefore doing two pointers makes not sense (to me at least, right now)

\n# Write a function that returns the indices of an array Arr for\n# elements that add up to a given number K\n# For example:\n# Given an array: [1,1,2,23,4,9,1