[BOJ] 4179 불! (G3)

Author: uiop5809

박예진/5주차/260126.cpp

@@ -0,0 +1,93 @@
+//https://www.acmicpc.net/problem/4179
+
+#include <iostream>
+#include <vector>
+#include <queue>
+using namespace std;
+
+int R, C;
+char arr[1001][1001];
+bool fvisited[1001][1001];
+bool jvisited[1001][1001];
+
+const int dx[4] = {-1, 0, 1, 0};
+const int dy[4] = {0, 1, 0, -1};
+ 
+struct Node {
+    int x, y;
+};
+
+bool OOB(int x, int y) {
+    return x < 0 || x >= R || y < 0 || y >= C;
+}
+
+Node now;
+queue<Node> fq;
+queue<Node> jq;
+
+void fbfs() {
+    int cnt = fq.size();
+    while(cnt--) {
+        Node now = fq.front();
+        fq.pop();
+
+        for(int dir = 0; dir < 4; dir++) {
+            int nx = now.x + dx[dir];
+            int ny = now.y + dy[dir];
+
+            if (OOB(nx, ny) || fvisited[nx][ny] || arr[nx][ny] == '#') continue;
+            fvisited[nx][ny] = true;
+            arr[nx][ny] = 'F';
+            fq.push({nx, ny});
+        }
+    }
+}
+
+int jbfs() {
+    int time = 0;
+    while(!jq.empty()) {
+        time++;
+        fbfs(); // 불 이동
+
+        int cnt = jq.size();
+        while(cnt--) {
+            Node now = jq.front();
+            jq.pop();
+
+            for(int dir = 0; dir < 4; dir++) {
+                int nx = now.x + dx[dir];
+                int ny = now.y + dy[dir];
+
+                if(OOB(nx, ny)) return time;
+                if(jvisited[nx][ny] || arr[nx][ny] == '#' || arr[nx][ny] == 'F') continue;
+                jvisited[nx][ny] = true;
+                arr[nx][ny] = 'J';
+                jq.push({nx, ny});
+            }
+        }
+    }
+    return -1;
+}
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(0); cout.tie(0);
+
+  cin >> R >> C;
+  for(int i = 0; i < R; i++){
+    for(int j = 0; j < C; j++){
+        cin >> arr[i][j];
+        if (arr[i][j] == 'J') {
+            jq.push({i, j});
+        } else if (arr[i][j] == 'F') {
+            fq.push({i, j});
+        }
+    }
+  }
+  
+  int time = jbfs();
+  if (time == -1) cout << "IMPOSSIBLE";
+  else cout << time;
+
+  return 0;
+}