10/24 회고록

import java.util.PriorityQueue; class Solution { public int[] solution(int[] array, int[][] commands) { int[] answer = new int[commands.length]; PriorityQueue<Integer> pq = new PriorityQueue<>(); for (int i = 0; i < commands.length; i++) { int left = commands[i][0]-1; //자를 지점의 left, right값 설정 int right = commands[i][1]; int n = commands[i][2]; for (int j = left; j < right; j++){ pq.add(array[j]); } for (int j = 0; j < n; j++){ answer[i] = pq.poll(); } pq.clear(); } return answer; } }

class Solution { public String solution(int[] numbers) { String[] s = new String[numbers.length]; StringBuilder sb = new StringBuilder(); for (int i = 0; i < numbers.length; i++) s[i] = String.valueOf(numbers[i]); Arrays.sort(s, new Comparator<String>() { //사전 순 내림차순 정렬 public int compare(String s1, String s2) { if (s1.charAt(0) == s2.charAt(0)) { int n1 = Integer.parseInt(s1 + s2); int n2 = Integer.parseInt(s2 + s1); return n2 - n1; } return s2.charAt(0) - s1.charAt(0); } }); for (int i = 0; i < s.length; i++) sb.append(s[i]); if (sb.charAt(0) == '0') return "0"; return sb.toString(); } }

public class Kth { public static void main(String[] args) { Kth kth = new Kth(); /* int[] arr = {1,5,2,6,3,7,4}; int[][] commands ={{2,5,3},{4,4,1},{1,7,3}};*/ int[] answer = kth.solution(new int[]{1, 5, 2, 6, 3, 7, 4}, new int[][]{{2, 5, 3}, {4, 4, 1}, {1, 7, 3}}); System.out.println(Arrays.toString(answer)); } public int[] solution(int[] arr, int[][] commands) { int[] answer = new int[commands.length]; //2차원의 배열의 행길이 for (int i = 0; i < commands.length; i++) { int[] temp = Arrays.copyOfRange(arr, commands[i][0] - 1, commands[i][1]); Arrays.sort(temp);//정렬 answer[i] = temp[commands[i][2] - 1]; } return answer; } }

public class KthQueue { public int[] solution(int[] arr, int[][] commands) { int[] answer = new int[commands.length]; for (int i = 0; i < commands.length; i++) { PriorityQueue<Integer> pq = new PriorityQueue<>(); for (int j = commands[i][0]-1; j < commands[i][1]; j++) { pq.add(arr[j]); } for (int j = 0; j < commands[i][2]; j++) { answer[i] = pq.poll(); } } return answer; } public static void main(String[] args) { KthQueue kthNum = new KthQueue(); int[] arr = new int[]{1, 5, 2, 6, 3, 7, 4}; int[][] commands = new int[][]{{2, 5, 3}, {4, 4, 1}, {1, 7, 3}}; System.out.println(Arrays.toString(kthNum.solution(arr, commands)));; } }

public int[] solution(int[] arr, int[][] commands) { int[] answer = new int[commands.length]; int idx = 0; for (int[] command :commands) { int[] slicedArr = Arrays.copyOfRange(arr, command[0]-1, command[1]); // array를 slice합니다. Arrays.sort(slicedArr); answer[idx++] = slicedArr[command[2]-1]; } return answer; }

public int getKthNum(int[] command) { int frIdx = command[0]; // 0번 from int toIdx = command[1]; // 1번 to int nth = command[2]; // n번째 int result = 0; // 문제에 0이 안나온다고 했기 때문에 3벌식 PriorityQueue<Integer> pq = new PriorityQueue<>(); for (int i = frIdx-1; i < toIdx ; i++) { // 1번부터 시작하니 -1 pq.add(arr[i]); } for (int i = 0; i < nth; i++) { result = pq.poll(); // stack의 pop과 비슷 } return result; } public int[] solution(int[] arr, int[][] commands) { this.arr = arr; int[] answer = new int[commands.length]; for (int i = 0; i < commands.length; i++) { answer[i] = getKthNum(commands[i]); } return answer; }

@Configuration public class UserDaoFactory { @Bean UserDao awsUserDao() { return new UserDao(dataSource()); } @Bean DataSource dataSource() { Map<String, String> env = System.getenv(); SimpleDriverDataSource dataSource = new SimpleDriverDataSource(); dataSource.setDriverClass(com.mysql.cj.jdbc.Driver.class); dataSource.setUrl(env.get("DB_HOST")); dataSource.setUsername(env.get("DB_USER")); dataSource.setPassword(env.get("DB_PASSWORD")); return dataSource; } }

@Configuration public class UserDaoFactory { @Bean UserDao awsUserDao() { return new UserDao(awsDataSource()); } @Bean UserDao localUserDao() { return new UserDao(localDataSource()); } @Bean DataSource awsDataSource() { Map<String, String> env = System.getenv(); SimpleDriverDataSource dataSource = new SimpleDriverDataSource(); dataSource.setDriverClass(com.mysql.cj.jdbc.Driver.class); dataSource.setUrl(env.get("DB_HOST")); dataSource.setUsername(env.get("DB_USER")); dataSource.setPassword(env.get("DB_PASSWORD")); return dataSource; } @Bean DataSource localDataSource() { Map<String, String> env = System.getenv(); SimpleDriverDataSource dataSource = new SimpleDriverDataSource(); dataSource.setDriverClass(com.mysql.cj.jdbc.Driver.class); dataSource.setUrl("localhost"); dataSource.setUsername("root"); dataSource.setPassword("12345678"); return dataSource; }}

public class UserDao { private DataSource dataSource; // DataSource를 의존하게 변경 public UserDao(DataSource dataSource) { this.dataSource = dataSource; // 생성자도 변경 } … public void jdbcContextWithStatementStrategy(StatementStrategy stmt) throws SQLException { Connection c = null; PreparedStatement pstmt = null; try { c = dataSource.getConnection(); // datasource를 사용하게 변경

public void deleteAll() throws SQLException { // "delete from users" StatementStrategy deleteAllStrategy = new StatementStrategy() { @Override public PreparedStatement makeStatement(Connection conn) throws SQLException { return conn.prepareStatement("delete from users"); } }; jdbcContextWithStatementStrategy(deleteAllStrategy); }

public void add(final User user) throws SQLException { // DB접속 (ex sql workbeanch실행) jdbcContextWithStatementStrategy(new StatementStrategy() { @Override public PreparedStatement makeStatement(Connection conn) throws SQLException { PreparedStatement pstmt = null; pstmt = conn.prepareStatement("INSERT INTO users(id, name, password) VALUES(?,?,?);"); pstmt.setString(1, user.getId()); pstmt.setString(2, user.getName()); pstmt.setString(3, user.getPassword()); return pstmt; } }); }