17-kokeunho

kokeunho/README.md

@@ -18,4 +18,5 @@
 | 14차시 | 2025.01.08 | 그래프 탐색 | [미로만들기](https://www.acmicpc.net/problem/2665) | [#55](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/55) |
 | 15차시 | 2025.01.12 | 조합론 | [격자상의 경로](https://www.acmicpc.net/problem/10164) | [#58](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/58) |
 | 16차시 | 2025.01.19 | 그래프 탐색 | [DFS와 BFS](https://www.acmicpc.net/problem/1260) | [#63](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/63) |
+| 17차시 | 2025.01.20 | 그래프 탐색 | [안전 영역](https://www.acmicpc.net/problem/2468) | [#64](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/64) |
 ---

kokeunho/그래프 탐색/17-kokeunho.java

@@ -0,0 +1,51 @@
+import java.util.*;
+
+public class Main {
+    static int n;
+    static int[][] map;
+    static boolean[][] visited;
+    static int[] dx = {-1, 1, 0, 0};
+    static int[] dy = {0, 0, -1, 1};
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        n = sc.nextInt();
+        map = new int[n][n];
+        visited = new boolean[n][n];
+
+        int max_height = 0;
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                map[i][j] = sc.nextInt();
+                max_height = Math.max(max_height, map[i][j]);
+            }
+        }
+
+        int max_area = 0;
+        for (int h = 0; h <= max_height; h++) {
+            visited = new boolean[n][n];
+            int safe_area = 0;
+            for (int i = 0; i < n; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (!visited[i][j] && map[i][j] > h) {
+                        dfs(i, j, h);
+                        safe_area++;
+                    }
+                }
+            }
+            max_area = Math.max(max_area, safe_area);
+        }
+        System.out.print(max_area);
+    }
+    public static void dfs(int startX, int startY, int height) {
+        visited[startX][startY] = true;
+        for (int i = 0; i < 4; i++) {
+            int nx = startX + dx[i];
+            int ny = startY + dy[i];
+            if (nx >= 0 && nx < n && ny >= 0 && ny < n && !visited[nx][ny] && map[nx][ny] > height) {
+                dfs(nx, ny, height);
+            }
+        }
+    }
+}