codewars #18 Convert string to camel case (5kyu)

 #18 Convert string to camel case

Complete the method/function so that it converts dash/underscore delimited words into camel casing. The first word within the output should be capitalized only if the original word was capitalized.

Examples:

// returns "theStealthWarrior"

toCamelCase("the-stealth-warrior") 

// returns "TheStealthWarrior"

toCamelCase("The_Stealth_Warrior")

오늘은 그나마 빨리 풀었다. 5랑 4레벨 차이가 어마어마한듯 ㅠ

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);
  }
}