1451_Rearrange_words_in_sentence

// https://leetcode.com/problems/rearrange-words-in-a-sentence/

// My approach

class Solution {
    public String arrangeWords(String text) {
        String result = "";
        String[] arr = text.toLowerCase().split(" ");
        for (int i=0;i<arr.length;i++) {
            for (int j=0;j<(arr.length - i - 1);j++) {
                if(arr[j].length() > arr[j+1].length()) {
                    String c = arr[j];
                    arr[j] = arr[j+1];
                    arr[j+1] = c;
                }
            }
        }
        StringBuffer sb = new StringBuffer();
        sb.append(Character.toUpperCase(arr[0].charAt(0))+arr[0].substring(1,arr[0].length())+" ");
        for(int i =1;i<arr.length-1;i++) {
            sb.append(arr[i] + " ");
        }
        sb.append(arr[arr.length-1]);
        return sb.toString();
    }
}

// Other solution 1

public String arrangeWords(String text) {
        String []s = text.toLowerCase().split(" ");
        Arrays.sort(s, (a,b) ->  a.length() - b.length());
        String ans = String.join(" ", s);
        return Character.toUpperCase(ans.charAt(0)) + ans.substring(1);
    }
    
    
// Solution 2

public String arrangeWords(String text) {
        TreeMap<Integer, StringBuilder> map=new TreeMap<>();
        String[] strs=text.split(" ");
        for(int i=0;i<strs.length;i++) {
            StringBuilder tmp=map.getOrDefault(strs[i].length(), new StringBuilder());
            tmp.append(strs[i]).append(" ");
            map.put(strs[i].length(), tmp);
        }
        StringBuilder sb=new StringBuilder();
        for(int k : map.keySet()) {
            StringBuilder tmp=map.get(k);
            if(tmp.charAt(0)<'a') tmp.setCharAt(0, (char)('a'+tmp.charAt(0)-'A'));
            sb.append(tmp);
        }
        if(sb.charAt(0)>'Z') sb.setCharAt(0, (char)('A'+sb.charAt(0)-'a'));
        return sb.deleteCharAt(sb.length()-1).toString();
    }