Given a word, create an object that stores the indexes of each letter in an array.

• Make sure the letters are the keys.
• Make sure the letters are symbols.
• Make sure the indexes are stored in an array and those arrays are values.

Examples

mapLetters("dodo") ➞ ["d": [0, 2], "o": [1, 3] ]

mapLetters("froggy") ➞ ["f": [0], "r": [1], "o": [2], "g": [3, 4], "y": [5] ]

mapLetters("grapes") ➞ [ "g": [0], "r": [1], "a": [2], "p": [3], "e": [4], "s": [5] ]

Notes

All strings given will be lowercase.