diff --git "a/BOJ/1000-5000353円262円210円/HW_1613.java" "b/BOJ/1000-5000353円262円210円/HW_1613.java"
new file mode 100644
index 00000000..8e1af2ad
--- /dev/null
+++ "b/BOJ/1000-5000353円262円210円/HW_1613.java"
@@ -0,0 +1,44 @@
+import java.io.*;
+import java.util.*;
+
+public class HW_1613 {
+ public static void main(String[] args) throws IOException{
+ BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+ StringTokenizer st = new StringTokenizer(br.readLine());
+ int N = Integer.parseInt(st.nextToken());
+ int K = Integer.parseInt(st.nextToken());
+
+ boolean[][] visited = new boolean[N+1][N+1]; // 방문 여부만 확인
+ for(int i=0; i<k; i++) { + st = new StringTokenizer(br.readLine()); + int a = Integer.parseInt(st.nextToken()); + int b = Integer.parseInt(st.nextToken()); + visited[a][b] = true; // 전후 관계 알고 있음 + } + + for(int k=1; k<=n; k++) { + for(int i=1; i<=n; i++) { + for(int j=1; j<=n; j++){ + if(visited[i][k] && visited[k][j]) { + visited[i][j] = true; + } + } + } + } + + int S = Integer.parseInt(br.readLine()); // 사건의 전후 관계를 알고 싶은 사건 쌍의 수 + for(int i=0; i<s; i++) { + st = new StringTokenizer(br.readLine()); + int a = Integer.parseInt(st.nextToken()); + int b = Integer.parseInt(st.nextToken()); + + if(visited[a][b]) { + System.out.println(-1); + } + else if(visited[b][a]) { + System.out.println(1); + } else System.out.println(0); + } + } +} + diff --git "a/BOJ/1000-5000353円262円210円/HW_2096.java" "b/BOJ/1000-5000353円262円210円/HW_2096.java" new file mode 100644 index 00000000..6c93220c --- /dev/null +++ "b/BOJ/1000-5000353円262円210円/HW_2096.java" @@ -0,0 +1,40 @@ +import java.io.*; +import java.util.*; + +public class Main { + public static void main(String[] args) throws IOException { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + int N = Integer.parseInt(br.readLine()); + + int[][] dp = new int[N][3]; + for (int i = 0; i < N; i++) { + StringTokenizer st = new StringTokenizer(br.readLine()); + for (int j = 0; j < 3; j++) { + dp[i][j] = Integer.parseInt(st.nextToken()); + } + } + + int[][] min = new int[N][3]; + int[][] max = new int[N][3]; + + for (int i = 0; i < 3; i++) { + min[0][i] = dp[0][i]; + max[0][i] = dp[0][i]; + } + + for (int i = 1; i < N; i++) { + max[i][0] = Math.max(max[i-1][0], max[i-1][1]) + dp[i][0]; + max[i][1] = Math.max(Math.max(max[i-1][0], max[i-1][1]), max[i-1][2]) + dp[i][1]; + max[i][2] = Math.max(max[i-1][1], max[i-1][2]) + dp[i][2]; + + min[i][0] = Math.min(min[i-1][0], min[i-1][1]) + dp[i][0]; + min[i][1] = Math.min(Math.min(min[i-1][0], min[i-1][1]), min[i-1][2]) + dp[i][1]; + min[i][2] = Math.min(min[i-1][1], min[i-1][2]) + dp[i][2]; + } + + int maxValue = Math.max(Math.max(max[N-1][0], max[N-1][1]), max[N-1][2]); + int minValue = Math.min(Math.min(min[N-1][0], min[N-1][1]), min[N-1][2]); + + System.out.println(maxValue + " " + minValue); + } +} diff --git "a/BOJ/1000-5000353円262円210円/HW_2955.java" "b/BOJ/1000-5000353円262円210円/HW_2955.java" new file mode 100644 index 00000000..ffc0d0be --- /dev/null +++ "b/BOJ/1000-5000353円262円210円/HW_2955.java" @@ -0,0 +1,111 @@ +import java.io.*; + +public class HW_2955 { + static int[][] board; + public static boolean[] row, col; + public static boolean[][] square; + static boolean error = false; + + public static void main(String[] args) throws Exception { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + + board = new int[9][9]; + for (int i = 0; i < 9; i++) { + String line = br.readLine(); + for (int j = 0; j < 9; j++) { + if (line.charAt(j) == '.') { + board[i][j] = 0; + } else board[i][j] = line.charAt(j) - '0'; + } + } + + while (true) { + if (!solve()) { + break; + } + } + + if (error) { + System.out.println("ERROR"); + } else { + for (int i = 0; i < 9; i++) { + for (int j = 0; j < 9; j++) { + if(board[i][j] == 0){ + System.out.print("."); + } else System.out.print(board[i][j]); + } + System.out.println(); + } + } + } + + public static boolean solve() { + for (int i = 1; i <= 9; i++) { + if (crossHatching(i)) { + return true; + } + } + return false; + } + + public static boolean crossHatching(int x) { + row = new boolean[9]; + col = new boolean[9]; + square = new boolean[3][3]; + + for (int i = 0; i < 9; i++) { + for (int j = 0; j < 9; j++) { + if (board[i][j] == x) { + if (row[i] &#124;&#124; col[j] &#124;&#124; square[i / 3][j / 3]) { + error = true; + return false; + } + row[i] = true; + col[j] = true; + square[i / 3][j / 3] = true; + } + } + } + for (int i = 0; i < 3; i++) { + for (int j = 0; j < 3; j++) { + if (!square[i][j]) { + if (check(i * 3, j * 3, x)) { + return true; + } + } + } + } + return false; + } + + public static boolean check(int curX, int curY, int x) { // x : 배치하려는 숫자 + int nx = -1; + int ny = -1; + int cnt = 0; + + for (int i = 0; i < 3; i++) { + for (int j = 0; j < 3; j++) { + if (board[curX + i][curY + j] == 0 && !row[curX + i] && !col[curY + j]) { + if (cnt == 0) { + nx = curX + i; + ny = curY + j; + cnt++; + } else { + return false; + } + } + } + } + + if (cnt == 0) { + error = true; + return false; + } + + board[nx][ny] = x; + row[nx] = true; + col[ny] = true; + + return true; + } +} \ No newline at end of file diff --git "a/CodeTree/2019-2020353円205円204円/HW_355円232円214円354円240円204円355円225円230円353円212円224円_353円271円231円355円225円230円.java" "b/CodeTree/2019-2020353円205円204円/HW_355円232円214円354円240円204円355円225円230円353円212円224円_353円271円231円355円225円230円.java" new file mode 100644 index 00000000..31d566ff --- /dev/null +++ "b/CodeTree/2019-2020353円205円204円/HW_355円232円214円354円240円204円355円225円230円353円212円224円_353円271円231円355円225円230円.java" @@ -0,0 +1,171 @@ +import java.io.*; +import java.util.*; + +public class HW_회전하는_빙하 { + static class Node { + int x, y; + public Node(int x, int y) { + this.x = x; + this.y = y; + } + } + + static int n, q, L; + static int[][] board, nextboard; + static boolean[][] visited; + static int[] dx = {0, 1, -1, 0}; // 오른쪽, 아래, 위, 왼쪽 + static int[] dy = {1, 0, 0, -1}; + static int max = 0; + + public static void main(String[] args) throws Exception { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + StringTokenizer st = new StringTokenizer(br.readLine()); + + n = Integer.parseInt(st.nextToken()); // 격자의 크기 (2^n * 2^n) + q = Integer.parseInt(st.nextToken()); // 회전 횟수 + L = (int) Math.pow(2, n); + board = new int[L][L]; + nextboard = new int[L][L]; + + // 보드 입력 + for (int i = 0; i < L; i++) { + st = new StringTokenizer(br.readLine()); + for (int j = 0; j < L; j++) { + board[i][j] = Integer.parseInt(st.nextToken()); + } + } + + // 회전 레벨 입력 + st = new StringTokenizer(br.readLine()); + while (q--> 0) {
+ int lv = Integer.parseInt(st.nextToken());
+ if (lv> 0) rotate(lv);
+ melt();
+ }
+
+ // 1. 남아있는 빙하의 총량 계산
+ int sum = 0;
+ for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + sum += board[i][j]; + } + } + System.out.println(sum); + + // 2. 가장 큰 얼음 군집 크기 계산 + visited = new boolean[L][L]; + max = 0; + for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + if (!visited[i][j] && board[i][j]> 0) {
+ max = Math.max(max, bfs(i, j));
+ }
+ }
+ }
+ System.out.println(max);
+ }
+
+ // 초기화
+ public static void initialize() {
+ for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + nextboard[i][j] = 0; + } + } + } + + + public static void rotate(int level) { + initialize(); // `nextboard` 초기화 + int boxSize = (int) Math.pow(2, level); + int halfSize = (int) Math.pow(2, level - 1); + + for (int i = 0; i < L; i += boxSize) { // 시계 방향 90도 회전 + for (int j = 0; j < L; j += boxSize) { + move(i, j, halfSize, 0); + move(i, j + halfSize, halfSize, 1); + move(i + halfSize, j, halfSize, 2); + move(i + halfSize, j + halfSize, halfSize, 3); + } + } + + for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + board[i][j] = nextboard[i][j]; // 배열 복사 + } + } + } + + // size`만큼의 하위 격자를 시계 방향으로 회전 + public static void move(int startX, int startY, int size, int dir) { + for (int i = startX; i < startX + size; i++) { + for (int j = startY; j < startY + size; j++) { + int nx = i + dx[dir] * size; + int ny = j + dy[dir] * size; + if (!isValid(nx, ny)) continue; + nextboard[nx][ny] = board[i][j]; + } + } + } + + public static void melt() { + initialize(); + + for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + if (board[i][j] != 0 && iceCnt(i, j) < 3) { + nextboard[i][j] = board[i][j] - 1; // -1 + } else { + nextboard[i][j] = board[i][j]; + } + } + } + + for (int i = 0; i < L; i++) { + for (int j = 0; j < L; j++) { + board[i][j] = nextboard[i][j]; + } + } + } + + public static int iceCnt(int x, int y) { + int cnt = 0; + for (int d = 0; d < 4; d++) { + int nx = x + dx[d]; + int ny = y + dy[d]; + + if (isValid(nx, ny) && board[nx][ny] != 0) { + cnt++; + } + } + return cnt; + } + + // BFS : 얼음 군집 크기를 계산 + public static int bfs(int x, int y) { + int size = 1; + Queue<int[]> queue = new LinkedList<strong>();
+ queue.offer(new int[]{x, y});
+ visited[x][y] = true;
+
+ while (!queue.isEmpty()) {
+ int[] pos = queue.poll();
+
+ for (int d = 0; d < 4; d++) { + int nx = pos[0] + dx[d]; + int ny = pos[1] + dy[d]; + + if (isValid(nx, ny) && !visited[nx][ny] && board[nx][ny]> 0) {
+ visited[nx][ny] = true;
+ queue.offer(new int[]{nx, ny});
+ size++;
+ }
+ }
+ }
+ return size;
+ }
+
+ public static boolean isValid(int x, int y) {
+ return x>= 0 && y>= 0 && x < L && y < L; + } +} \ No newline at end of file diff --git a/Programmers/Level2/HW_181188.java b/Programmers/Level2/HW_181188.java new file mode 100644 index 00000000..ee235d65 --- /dev/null +++ b/Programmers/Level2/HW_181188.java @@ -0,0 +1,21 @@ +import java.util.*; +// 구하는 것 : 모든 폭격 미사일을 요격하기 위해 필요한 요격 미사일 수의 최솟값 +class Solution { + public int solution(int[][] targets) { + Arrays.sort(targets, (a, b) -> Integer.compare(a[1], b[1])); // e구간 기준 정렬
+
+ int cnt = 0; // 요격 미사일 개수
+ double endShoot = Integer.MIN_VALUE; // 미사일 쏘는 위치
+
+ for(int i=0; i<targets.length; i++){ + int s = targets[i][0]; // s + int e = targets[i][1]; // e + + if(endShoot<s){ // 마지막 발사 위치보다 현재 시작 구간이 더 크면 + cnt++; // 새로운 미사일 설치 + endShoot = e-0.5; // 개구간 = 범위 포함X : 임의로 실수를 빼줌 + } + } + return cnt; + } +} \ No newline at end of file diff --git a/Programmers/Level3/HW_150366.java b/Programmers/Level3/HW_150366.java new file mode 100644 index 00000000..225352dd --- /dev/null +++ b/Programmers/Level3/HW_150366.java @@ -0,0 +1,124 @@ +import java.util.*; + +class HW_150366 { + static int n = 2500; + static int grp[]; + static String values[]; + + public String[] solution(String[] commands) { + grp = new int[n]; + values = new String[n]; + List<string> answers = new ArrayList<strong>();
+
+ for(int i = 0; i < n; i++){ + grp[i] = i; + } + + StringTokenizer st; + for(int i = 0; i < commands.length; i++){ + st = new StringTokenizer(commands[i]); + int r, c; + String v; + switch(st.nextToken()){ + case "UPDATE" : // UPDATE 추출 + String v1 = st.nextToken(); // v1 추출 + String v2 = st.nextToken(); // v2 추출 + + if(st.hasMoreTokens()){ // 남아있는 토큰이 있는 경우 (UPDATE v1 v2 value) + String value = st.nextToken(); // value 추출 + r = Integer.parseInt(v1) - 1; + c = Integer.parseInt(v2) - 1; + values[find(r * 50 + c)] = value; + } + else{ // UPDATE v1 v2 + for(int j = 0; j < n; j++){ + if(values[find(j)] != null && values[find(j)].equals(v1)){ + values[find(j)] = v2; + } + } + } + break; + + case "MERGE" : + int r1 = Integer.parseInt(st.nextToken()) - 1; + int c1 = Integer.parseInt(st.nextToken()) - 1; + int r2 = Integer.parseInt(st.nextToken()) - 1; + int c2 = Integer.parseInt(st.nextToken()) - 1; + + int num1 = r1*50 + c1; + int num2 = r2*50 + c2; + + // 값이 없는 표이 대표가 되지 않게 처리 + if(values[find(num1)] == null && values[find(num2)] != null){ + int temp = num1; + num1 = num2; + num2 = temp; + } + union(num1, num2); // 두 칸 병합 + break; + + case "UNMERGE" : + r = Integer.parseInt(st.nextToken()) - 1; + c = Integer.parseInt(st.nextToken()) - 1; + + int g = find(r*50 +c); // 대표 칸 찾기 + v = values[g]; // 대표 칸의 값을 저장 + + // 경로 압축 + for(int j = 0; j < n; j++){ + find(j); + } + + for(int j = 0; j < n; j++){ + if(find(j) == g){ + grp[j] = j; // 동일한 대표 칸을 가진 경우 초기화 + + if(j == r*50 + c){ + values[j] = v; // 지정된 칸의 값 유지 + }else{ + values[j] = null; // 나머지 칸 초기화 + } + } + } + break; + + case "PRINT" : + r = Integer.parseInt(st.nextToken()) - 1; + c = Integer.parseInt(st.nextToken()) - 1; + + v = values[find(r*50 + c)]; + + if(v == null){ + answers.add("EMPTY"); + } + else answers.add(v); + break; + } + } + String[] answer = new String[answers.size()]; + for(int i = 0; i < answers.size(); i++){ + answer[i] = answers.get(i); + } + return answer; + } + + // 원소가 속한 그룹 알아내기 + static int find(int idx){ + if(idx == grp[idx]){ + return idx; + } + return grp[idx] = find(grp[idx]); + } + + // 그룹 합치기 + static void union(int g1, int g2){ + g1 = find(g1); + g2 = find(g2); + + if(g1 == g2){ + return; + } + values[g2] = null; + grp[g2] = g1; + } +} \ No newline at end of file diff --git a/Programmers/Level3/HW_42884.java b/Programmers/Level3/HW_42884.java new file mode 100644 index 00000000..e1bba9b1 --- /dev/null +++ b/Programmers/Level3/HW_42884.java @@ -0,0 +1,22 @@ +// 모든 차량이 한번은 단속용 카메라를 만나도록하는 최소 카메라 설치 개수 +import java.util.*; +class HW_42884 { + public int solution(int[][] routes) { + Arrays.sort(routes, (a,b) -> Integer.compare(a[1], b[1])); // 나간 지점 기준 정렬
+
+ // 단속카메라 탐색
+ int cnt = 0; // 카메라 개수
+ int endCamera= Integer.MIN_VALUE; // 처음엔 카메라 설치X
+
+ for(int i=0; i<routes.length; i++){
+ int s = routes[i][0]; // 진입 지점
+ int e = routes[i][1]; // 진출 지점(나감)
+
+ if(endCamera<s){ // 설치되지 않은 지점
+ cnt++; // 카메라 설치
+ endCamera = e; // 나가는 지점에 카메라 설치!
+ }
+ }
+ return cnt;
+ }
+}
\ No newline at end of file
diff --git "a/SQL/10354円243円274円354円260円250円/HW_Second Highest Salary.SQL" "b/SQL/10354円243円274円354円260円250円/HW_Second Highest Salary.SQL"
new file mode 100644
index 00000000..daadcb27
--- /dev/null
+++ "b/SQL/10354円243円274円354円260円250円/HW_Second Highest Salary.SQL"	
@@ -0,0 +1,5 @@
+SELECT MAX(Salary) as SecondHighestSalary
+FROM (SELECT salary, dense_rank() over(order by salary desc) as rk
+ FROM Employee
+ ) Employee
+where rk = 2;
\ No newline at end of file
diff --git "a/SQL/10354円243円274円354円260円250円/HW_354円203円201円355円222円210円354円235円204円 352円265円254円353円247円244円355円225円234円 355円232円214円354円233円220円 353円271円204円354円234円250円 352円265円254円355円225円230円352円270円260円.SQL" "b/SQL/10354円243円274円354円260円250円/HW_354円203円201円355円222円210円354円235円204円 352円265円254円353円247円244円355円225円234円 355円232円214円354円233円220円 353円271円204円354円234円250円 352円265円254円355円225円230円352円270円260円.SQL"
new file mode 100644
index 00000000..0474b86f
--- /dev/null
+++ "b/SQL/10354円243円274円354円260円250円/HW_354円203円201円355円222円210円354円235円204円 352円265円254円353円247円244円355円225円234円 355円232円214円354円233円220円 353円271円204円354円234円250円 352円265円254円355円225円230円352円270円260円.SQL"	
@@ -0,0 +1,18 @@
+SELECT
+ YEAR(A.SALES_DATE) AS YEAR,
+ MONTH(A.SALES_DATE) AS MONTH,
+ COUNT(DISTINCT A.USER_ID) AS PURCHASED_USERS,
+ ROUND(
+ COUNT(DISTINCT A.USER_ID) /
+ (SELECT COUNT(*) FROM USER_INFO WHERE YEAR(JOINED) = 2021), 1)
+ AS PUCHASED_RATIO
+FROM
+ ONLINE_SALE A
+ JOIN
+ USER_INFO B ON A.USER_ID = B.USER_ID
+WHERE
+ YEAR(B.JOINED) = 2021
+GROUP BY
+ YEAR(A.SALES_DATE), MONTH(A.SALES_DATE)
+ORDER BY
+ year, month;
\ No newline at end of file
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