[알고리즘문제풀기] 수 조작하기 2

문제

내가 작성한 정답

// String
class Solution {
    public String solution(int[] numLog) {
        String answer = "";
        for(int i=1; i<numLog.length; i++){
            int num = numLog[i] - numLog[i-1];
            answer += (num == 1)? "w": (num == -1 )? "s" : (num == 10)? "d": "a";
        }
        return answer;
    }
}

// StringBuilder
class Solution {
    public String solution(int[] numLog) {
        StringBuilder sb = new StringBuilder();
        for(int i=1; i<numLog.length; i++){
            int num = numLog[i] - numLog[i-1];
            sb.append((num == 1)? "w": (num == -1 )? "s" : (num == 10)? "d": "a");
        }
        return sb.toString();
    }
}

// stream
import java.util.stream.*;
class Solution {
    public String solution(int[] numLog) {
        return IntStream.range(1,numLog.length)
                .mapToObj(i-> {
                    int num = numLog[i] - numLog[i - 1];
                    return (num == 1)? "w": (num == -1 )? "s" : (num == 10)? "d": "a";
                })
                .collect(Collectors.joining());
    }
}

다른 사람들의 정답

class Solution {
    public String solution(int[] numLog) {
        String answer = "";
        for(int i=1; i<numLog.length; i++){
            int j = numLog[i-1] - numLog[i];
            switch(j){
                case -1 : answer+='w'; break;
                case 1 : answer+='s'; break;
                case -10 : answer+='d'; break;
                case 10 : answer+='a'; break;
            }
        }
        return answer;
    }
}