From b5ce1cbd8053b49a48f28be66f43e6e4910c69b0 Mon Sep 17 00:00:00 2001
From: kangrae <kangrae0501@gmail.com>
Date: Fri, 18 Jul 2025 15:30:46 +0900
Subject: [PATCH] =?UTF-8?q?2025-07-18=20=EC=B9=98=EC=A6=88?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 kangrae-jo/Queue/30-kangrae-jo.cpp | 90 ++++++++++++++++++++++++++++++
 kangrae-jo/README.md               |  1 +
 2 files changed, 91 insertions(+)
 create mode 100644 kangrae-jo/Queue/30-kangrae-jo.cpp

diff --git a/kangrae-jo/Queue/30-kangrae-jo.cpp b/kangrae-jo/Queue/30-kangrae-jo.cpp
new file mode 100644
index 0000000..162f4b5
--- /dev/null
+++ b/kangrae-jo/Queue/30-kangrae-jo.cpp
@@ -0,0 +1,90 @@
+#include <iostream>
+#include <queue>
+#include <vector>
+
+using namespace std;
+
+const int AIR = -1;
+const int EMPTY = 0;
+const int CHEESE = 1;
+const int OFFSET[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
+
+int N, M;
+vector<vector<int>> board;
+
+bool isIn(int y, int x) { return 0 <= y && y < N && 0 <= x && x < M; }
+
+void markAir() {
+    vector<vector<bool>> visited(N, vector<bool>(M, false));
+    queue<pair<int, int>> q;
+    q.push({0, 0});
+    visited[0][0] = true;
+    board[0][0] = AIR;
+
+    while (!q.empty()) {
+        auto [y, x] = q.front();
+        q.pop();
+
+        for (int dir = 0; dir < 4; dir++) {
+            int y_ = y + OFFSET[dir][0];
+            int x_ = x + OFFSET[dir][1];
+            if (isIn(y_, x_) && !visited[y_][x_] && board[y_][x_] == EMPTY) {
+                visited[y_][x_] = true;
+                board[y_][x_] = AIR;
+                q.push({y_, x_});
+            }
+        }
+    }
+}
+
+bool melt() {
+    vector<pair<int, int>> cheeseToMelt;
+    for (int y = 0; y < N; y++) {
+        for (int x = 0; x < M; x++) {
+            if (board[y][x] == CHEESE) {
+                int contact = 0;
+                for (int dir = 0; dir < 4; dir++) {
+                    int y_ = y + OFFSET[dir][0];
+                    int x_ = x + OFFSET[dir][1];
+                    if (isIn(y_, x_) && board[y_][x_] == AIR) contact++;
+                }
+                if (contact >= 2) cheeseToMelt.push_back({y, x});
+            }
+        }
+    }
+    for (auto [y, x] : cheeseToMelt) board[y][x] = EMPTY;
+
+    return !cheeseToMelt.empty();
+}
+
+void resetAir() {
+    for (int y = 0; y < N; y++) {
+        for (int x = 0; x < M; x++) {
+            if (board[y][x] == AIR) board[y][x] = EMPTY;
+        }
+    }
+}
+
+int main() {
+    ios_base::sync_with_stdio(0);
+    cout.tie(0);
+    cin.tie(0);
+
+    cin >> N >> M;
+    board.assign(N, vector<int>(M));
+    for (int y = 0; y < N; y++) {
+        for (int x = 0; x < M; x++) {
+            cin >> board[y][x];
+        }
+    }
+
+    int answer = 0;
+    while (++answer) {
+        markAir();           // 바깥 공기 == AIR
+        if (!melt()) break;  // 녹일 치즈 없으면 종료
+        resetAir();          // AIR = EMPTY 복구 
+    }
+    cout << answer - 1;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/kangrae-jo/README.md b/kangrae-jo/README.md
index 6f1899e..6993d96 100644
--- a/kangrae-jo/README.md
+++ b/kangrae-jo/README.md
@@ -30,3 +30,4 @@
 | 26차시 | 2024.05.19 |  DFS  | [길 찾기 게임](https://school.programmers.co.kr/learn/courses/30/lessons/42892)|[#103](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/103)|
 | 27차시 | 2024.06.01 |  DFS  | [개미굴](https://www.acmicpc.net/problem/14725)|[#107](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/107)|
 | 28차시 | 2024.06.10 |  BFS  | [경주로 건설](https://school.programmers.co.kr/learn/courses/30/lessons/67259)|[#110](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/110)|
+| 30차시 | 2024.07.18 |  BFS  | [치즈](https://www.acmicpc.net/problem/2638)|[#117](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/117)|