solve: 코딩테스트 문제 풀이 - 18일차

Author: OhChangEun

2025-08-30/오창은/[solved] 백준_LCS.java

@@ -0,0 +1,30 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String str1 = br.readLine();
+        String str2 = br.readLine();
+
+        int n = str1.length();
+        int m = str2.length();
+
+        int[][] dp = new int[n+1][m+1];
+
+        for (int i=1; i<=n; i++) {
+            for (int j=1; j<=m; j++) {
+                if (str1.charAt(i-1) == str2.charAt(j-1)) {
+                    dp[i][j] = dp[i-1][j-1] + 1;
+                } else {
+                    dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]);
+                }
+            }
+        }
+
+        System.out.println(dp[n][m]);
+    }
+}

2025-08-30/오창은/[solved] 백준_별 찍기.java

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+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+    static char[][] canvas;
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int N = Integer.parseInt(br.readLine());
+
+        int height = N;
+        int weight = 2 * N - 1;
+        canvas = new char[height][weight];
+
+        for (int i=0; i<height; i++) {
+            Arrays.fill(canvas[i], ' ');
+        }
+
+        draw(0, N-1, N);
+
+        StringBuilder sb = new StringBuilder();
+        for (int i=0; i<height; i++) {
+            sb.append(canvas[i]).append('\n');
+        }
+        System.out.print(sb.toString());
+    }
+
+    public static void draw(int row, int col, int size) {
+        if (size == 3) {
+            canvas[row][col] = '*';
+            canvas[row+1][col-1] = '*';
+            canvas[row+1][col+1] = '*';
+
+            for (int i=-2; i<=2; i++) {
+                canvas[row+2][col+i] = '*';
+            }
+            return;
+        }
+
+        int half = size / 2;
+        draw(row, col, half);
+        draw(row + half, col - half, half);
+        draw(row + half, col + half, half);
+    }
+}

2025-08-30/오창은/[solved] 백준_파이프 옮기기.java

@@ -0,0 +1,55 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+    static int N;
+    static int[][] room;
+    static int count = 0;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+
+        room = new int[N][N];
+        for (int i=0; i<N; i++) {
+            String[] input = br.readLine().split(" ");
+            for (int j=0; j<N; j++) {
+                room[i][j] = Integer.parseInt(input[j]);
+            }
+        }
+
+        dfs(1, 0, 0);
+        System.out.println(count);
+    }
+
+    // 0: 가로, 1: 세로, 2: 대각선
+    public static void dfs(int x, int y, int dir) {
+        if (x == N-1 && y == N-1) {
+            count++;
+            return;
+        }
+
+        if (dir == 0 || dir == 2) {
+            int nx = x + 1, ny = y;
+            if (nx < N && room[ny][nx] == 0) {
+                dfs(nx, ny, 0);
+            }
+        }
+        if (dir == 1 || dir == 2) {
+            int ny = y + 1, nx = x;
+            if (ny < N && room[ny][nx] ==0) {
+                dfs(nx, ny, 1);
+            }
+        }
+        if (dir == 0 || dir == 1 || dir ==2) {
+            int nx = x + 1, ny = y + 1;
+            if (nx < N && ny < N) {
+                if (room[y][nx] == 0 && room[ny][x] == 0 && room[ny][nx] == 0) {
+                    dfs(nx, ny, 2);
+                }
+            }
+        }
+    }
+}