Day 24. 코딩 기초 트레이닝(Java)

1. 커피 심부름

https://school.programmers.co.kr/learn/courses/30/lessons/181837

프로그래머스

class Solution {
    public int solution(String[] order) {
        int answer = 0;
        
        for(String order_item : order) {
            if(order_item.contains("cafelatte")) {
                answer += 5000;
            } else {
                answer += 4500;
            }
        }
        
        return answer;
    }
}

 

2. 그림 확대

https://school.programmers.co.kr/learn/courses/30/lessons/181836

프로그래머스

▼ 방법 1

class Solution {
    public String[] solution(String[] picture, int k) {
        String[] answer = new String[picture.length * k];
        String dot = ".".repeat(k);
        String x = "x".repeat(k);
        int idx = 0;
        
        for(String s : picture) {
            for(int i = 0; i < k; i++) {
                answer[idx++] = s.replace(".", dot).replace("x", x);
            }
        }
        
        return answer;
    }
}

 

▼ 방법 2

class Solution {
    public String[] solution(String[] picture, int k) {
        String[] answer = new String[picture.length * k];
        
        for(int i = 0; i < answer.length; i++) {
            answer[i] = "";
        }
        
        for(int i = 0; i < answer.length; i++) {
            for(int j = 0; j < picture[0].length(); j++) {
                answer[i] += String.valueOf(picture[i / k].charAt(j)).repeat(k);
            }
        }
        
        return answer;
    }
}

 

3. 조건에 맞게 수열 변환하기 3

https://school.programmers.co.kr/learn/courses/30/lessons/181835

프로그래머스

▼ 방법 1

class Solution {
    public int[] solution(int[] arr, int k) {
        int[] answer = new int[arr.length];
        
        for(int i = 0; i < arr.length; i++) {
            if(k % 2 == 1) {
                answer[i] = arr[i] * k;
            } else {
                answer[i] = arr[i] + k;
            }
        }
        
        return answer;
    }
}

 

▼ 방법 2

import java.util.stream.IntStream;

class Solution {
    public int[] solution(int[] arr, int k) {
        int[] answer = {};
        
        if(k % 2 == 1) {
            answer = IntStream.of(arr).map(i -> i * k).toArray();
        } else {
            answer = IntStream.of(arr).map(i -> i + k).toArray();
        }
        
        return answer;
    }
}

 

▼ 방법 3

import java.util.Arrays;

class Solution {
    public int[] solution(int[] arr, int k) {
        int[] answer = {};
        
        if(k % 2 == 1) {
            answer = Arrays.stream(arr).map(i -> i * k).toArray();
        } else {
            answer = Arrays.stream(arr).map(i -> i + k).toArray();
        }
        
        return answer;
    }
}

 

▼ 방법 4

import java.util.Arrays;

class Solution {
    public int[] solution(int[] arr, int k) {
        int[] answer = {};
        
        answer = Arrays.stream(arr).map(i -> k % 2 == 1 ? i * k : i + k).toArray();
        
        return answer;
    }
}

 

4. l로 만들기

https://school.programmers.co.kr/learn/courses/30/lessons/181834

프로그래머스

▼ 방법 1

class Solution {
    public String solution(String myString) {
        String answer = "";
        
        for(char c : myString.toCharArray()) {
            if(c < 'l') {
                answer += 'l';
            } else {
                answer += c;
            }
        }
        
        return answer;
    }
}

 

▼ 방법 2

class Solution {
    public String solution(String myString) {
        String answer = "";
        
        answer = myString.replaceAll("[^l-z]", "l");
        
        return answer;
    }
}

 

5. 특별한 이차원 배열 1

https://school.programmers.co.kr/learn/courses/30/lessons/181833

프로그래머스

▼ 방법 1

class Solution {
    public int[][] solution(int n) {
        int[][] answer = new int[n][n];
        
        for(int i = 0; i < answer.length; i++) {
            for(int j = 0; j < answer[i].length; j++) {
                if(i == j) {
                    answer[i][j] = 1;
                } else {
                    answer[i][j] = 0;
                }
            }
        }
        
        return answer;
    }
}

 

▼ 방법 2

class Solution {
    public int[][] solution(int n) {
        int[][] answer = new int[n][n];
        
        for(int i = 0; i < n; i++) {
            answer[i][i] = 1;
        }
        
        return answer;
    }
}

 

▼ 방법 3

import java.util.stream.IntStream;

class Solution {
    public int[][] solution(int n) {
        int[][] answer = {};
        
        answer = IntStream.range(0, n).mapToObj(i -> IntStream.range(0, n).map(j -> j == i ? 1 : 0).toArray()).toArray(int[][]::new);
        
        return answer;
    }
}