[BOJ] 2234 성곽 (G3)

Author: uiop5809

박예진/4주차/260121.cpp

@@ -0,0 +1,90 @@
+//https://www.acmicpc.net/problem/2234
+
+#include <iostream>
+#include <algorithm>
+#include <vector>
+#include <queue>
+using namespace std;
+
+struct Node {
+  int x, y;
+};
+
+int N, M, arr[51][51];
+bool visited[51][51];
+int roomIdx[51][51];
+// 서, 북, 동, 남
+const int dx[4] = {0, -1, 0, 1};
+const int dy[4] = {-1, 0, 1, 0};
+
+bool OOB(int x, int y){
+  if (x < 0 || x >= N || y < 0 || y >= M) return true;
+  return false;
+}
+
+int bfs(int x, int y, int idx) {
+  queue<Node> q;
+  q.push({x, y});
+  visited[x][y] = true;
+  int cnt = 0;
+
+  while(!q.empty()) {
+    Node now = q.front(); q.pop();
+    roomIdx[now.x][now.y] = idx;
+    cnt++;
+
+    for(int dir = 0; dir < 4; dir++){
+      int nx = now.x + dx[dir];
+      int ny = now.y + dy[dir];
+
+      if (OOB(nx, ny) || visited[nx][ny]) continue;
+      if (arr[now.x][now.y] & (1 << dir)) continue; // 벽이 있다면
+      q.push({nx, ny});
+      visited[nx][ny] = true;
+    }
+  }
+  return cnt;
+}
+
+int main(){
+  cin >> M >> N;
+  for(int i = 0; i < N; i++){
+    for(int j = 0; j < M; j++){
+      cin >> arr[i][j];
+    }
+  }
+
+  // bfs 돌려서 방의 개수, 넓이 구하기
+  int roomCnt = 0;
+  int roomSize = 0;
+  int res = 0;
+  vector<int> rooms;
+
+  for(int i = 0; i < N; i++){
+    for(int j = 0; j < M; j++){
+      if (!visited[i][j]) {
+        int num = bfs(i, j, roomCnt);
+        roomCnt++;
+        roomSize = max(roomSize, num);
+        rooms.push_back(num);
+      }
+    }
+  }
+
+  // 각 연결되어 있는 방 검색
+  for(int i = 0; i < N; i++){
+    for(int j = 0; j < M; j++){
+      for(int dir = 0; dir < 4; dir++){
+        int nx = i + dx[dir];
+        int ny = j + dy[dir];
+
+        if (OOB(nx, ny)) continue;
+        if (roomIdx[i][j] != roomIdx[nx][ny]) {
+          res = max(res, rooms[roomIdx[i][j]] + rooms[roomIdx[nx][ny]]);
+        }
+      }
+    }
+  }
+
+  cout << roomCnt << "\n" << roomSize << "\n" << res;
+}