Day 13 - 코딩테스트 입문(Java)

1. 컨트롤 제트

https://school.programmers.co.kr/learn/courses/30/lessons/120853

프로그래머스

▼ 방법 1

class Solution {
    public int solution(String s) {
        int answer = 0;
        String[] str = s.split(" ");
        
        for(int i = 0; i < str.length; i++) {
            if(str[i].equals("Z")) {
                answer -= Integer.parseInt(str[i - 1]);
            } else {
                answer += Integer.parseInt(str[i]);
            }
        }
        
        return answer;
    }
}

 

▼ 방법 2

import java.util.Stack;

class Solution {
    public int solution(String s) {
        int answer = 0;
        Stack<Integer> stack = new Stack<>();
        
        for(String str : s.split(" ")) {
            if(str.equals("Z")) {
                stack.pop();
            } else {
                stack.push(Integer.parseInt(str));
            }
        }
        
        for(int i : stack) {
            answer += i;
        }
        
        return answer;
    }
}

 

2. 배열 원소의 길이

https://school.programmers.co.kr/learn/courses/30/lessons/120854

프로그래머스

▼ 방법 1

class Solution {
    public int[] solution(String[] strlist) {
        int[] answer = new int[strlist.length];
        
        for(int i = 0; i < strlist.length; i++) {
            answer[i] = strlist[i].length();
        }
        
        return answer;
    }
}

 

▼ 방법 2

import java.util.Arrays;

class Solution {
    public int[] solution(String[] strlist) {
        int[] answer = {};
        
        answer = Arrays.stream(strlist).mapToInt(String::length).toArray();
        
        return answer;
    }
}

 

3. 중복된 문자 제거

https://school.programmers.co.kr/learn/courses/30/lessons/120888

프로그래머스

▼ 방법 1

import java.util.Set;
import java.util.LinkedHashSet;

class Solution {
    public String solution(String my_string) {
        String answer = "";
        Set<String> answerSet = new LinkedHashSet<>();
        
        for(String s : my_string.split("")) {
            answerSet.add(s);
        }
        
        for(String s : answerSet) {
            answer += s;
        }
        
        return answer;
    }
}

 

▼ 방법 2

import java.util.Set;
import java.util.LinkedHashSet;
import java.util.Arrays;

class Solution {
    public String solution(String my_string) {
        String answer = "";
        Set<String> answerSet = new LinkedHashSet<String>(Arrays.asList(my_string.split("")));
        
        answer = String.join("", answerSet);
        
        return answer;
    }
}

 

▼ 방법 3

import java.util.stream.Collectors;

class Solution {
    public String solution(String my_string) {
        String answer = "";
        
        answer = my_string.chars().mapToObj(Character::toString).distinct().collect(Collectors.joining());
        
        return answer;
    }
}

 

4. 삼각형의 완성조건 (1)

https://school.programmers.co.kr/learn/courses/30/lessons/120889

프로그래머스

import java.util.Arrays;

class Solution {
    public int solution(int[] sides) {
        int answer = 0;
        
        Arrays.sort(sides);
        
        answer = sides[2] < sides[0] + sides[1] ? 1 : 2;
        
        return answer;
    }
}