RearrangeWordsInASentence.js

// Source : https://leetcode.com/problems/rearrange-words-in-a-sentence
// Author : Dean Shi
// Date   : 2020-05-17

/***************************************************************************************
 * Given a sentence text (A sentence is a string of space-separated words) in the
 * following format:
 * 
 * First letter is in upper case.
 * Each word in text are separated by a single space.
 * 
 * Your task is to rearrange the words in text such that all words are rearranged in an
 * increasing order of their lengths. If two words have the same length, arrange them
 * in their original order.
 * 
 * Return the new text following the format shown above.
 * 
 * Example 1:
 * 
 * Input: text = "Leetcode is cool"
 * Output: "Is cool leetcode"
 * Explanation: There are 3 words, "Leetcode" of length 8, "is" of length 2 and "cool"
 * of length 4.
 * Output is ordered by length and the new first word starts with capital letter.
 * 
 * Example 2:
 * 
 * Input: text = "Keep calm and code on"
 * Output: "On and keep calm code"
 * Explanation: Output is ordered as follows:
 * "On" 2 letters.
 * "and" 3 letters.
 * "keep" 4 letters in case of tie order by position in original text.
 * "calm" 4 letters.
 * "code" 4 letters.
 * 
 * Example 3:
 * 
 * Input: text = "To be or not to be"
 * Output: "To be or to be not"
 * 
 * Constraints:
 * 
 * text begins with a capital letter and then contains lowercase letters and single
 * space between words.
 * 1 <= text.length <= 10^5
 * 
 * 
 ***************************************************************************************/

/**
 * @param {string} text
 * @return {string}
 */
var arrangeWords = function(text) {
    const table = {}

    text.toLowerCase().split(" ").forEach((str) => {
        table[str.length] = (table[str.length] || "") + str + " "
    })

    return capitalizeFirstLetter(Object.values(table).join("")).trim()
};

function capitalizeFirstLetter(string) {
  return string.charAt(0).toUpperCase() + string.slice(1);
}