개발이 하고 싶어요

import java.lang.StringBuilder;
import java.util.StringTokenizer;

class Solution{

  static String toCamelCase(String s){
  
		StringTokenizer tokenizer = new StringTokenizer(s,"-|_|");
		StringBuilder result = new StringBuilder();
		
		int index = 0;
		while(tokenizer.hasMoreTokens()) {
			String token = tokenizer.nextToken();
			if(index ==0) {
				result.append(token);
			}else {
				result.append(token.substring(0, 1).toUpperCase() + token.substring(1));
			}
			index++;
		}
		
		return result.toString();
  }
}

두번째 풀이

import java.util.Arrays;

class Solution{

  static String toCamelCase(String s){
  
	 String [] words =s.split("-|_");
	 return Arrays.stream(words, 1, words.length)
				.map(word -> word.substring(0, 1).toUpperCase() + word.substring(1))
				.reduce(words[0], String::concat);
  }
}

import java.io.UnsupportedEncodingException;

public class JavaUnicodeEncoder {
    public static String decode(final String input) throws UnsupportedEncodingException {
    	  String[] arr = input.replace("\\","").split("u");
    	  StringBuilder result = new StringBuilder();
    	  for(String  str :arr){
    		  if(str.length()!=0) {
    			  int hex = Integer.parseInt(str, 16);
    			  result.append((char)hex);
    		  }
    	  }
    	  return result.toString();
    }

    public static String encode(String input){
     	  StringBuilder builder = new StringBuilder();
		  for (char c : input.toCharArray()) {
    		  builder.append("\\u" + Integer.toHexString(c | 0x10000).substring(1));
    	  };
	      return builder.toString();
    }
}

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;	

class Solution {
		public static String rangeExtraction(int[] arr) {
    		int length = arr.length;
        Arrays.sort(arr);
        int idx = 0, idx2 = 0;
        List<String> result = new ArrayList<String>();
        while (idx < length) {
            while (++idx2 < length && arr[idx2] - arr[idx2 - 1] == 1);
            if (idx2 - idx > 2) {
            	result.add(new String(arr[idx]+"-"+arr[idx2 - 1]));
                idx = idx2;
            } else {
                for (; idx < idx2; idx++)
                	result.add(new String(arr[idx]+""));
            }
        }
		
        
        return result.stream().collect(Collectors.joining(","));
    }
}

public class CalculateRotation {
  static int shiftedDiff(String first, String second){
    for(int i=0; i< second.length(); i++){
        if(second.equals(first))
            return i;
        second = second.substring(1)+second.charAt(0);
    }
    return -1;
  }
}

나름 군더더기 없이 했다고 생각했는데 

public class CalculateRotation {
  static int shiftedDiff(String first, String second){
    if(first.length() !=  second.length())
      return -1;
    return (second+second).indexOf(first);
  }
}