5-g0rnn

g0rnn/DFS,BFS/5-g0rnn.cpp

@@ -0,0 +1,103 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <climits>
+
+#define EMPTY 0
+#define WALL 1
+#define VIRUS 2
+#define VISITED 3
+
+using namespace std;
+
+int n, m;
+int safe = 0, virus = 0;
+int maxSafe = INT_MIN;
+vector<vector<int>> lab;
+queue<pair<int, int>> q;
+int offset[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
+
+bool canMove(const vector<vector<int>> &tmp, int x, int y)
+{
+    return x >= 0 && x < m && y >= 0 && y < n && tmp[y][x] == EMPTY;
+}
+
+void bfs()
+{
+    int all_virus = 0;
+    vector<vector<int>> tmp_lab = lab;
+    queue<pair<int, int>> tmpq = q;
+    while (!tmpq.empty())
+    {
+        int x = tmpq.front().first;
+        int y = tmpq.front().second;
+        all_virus++;
+        tmpq.pop();
+
+        for (int dir = 0; dir < 4; dir++)
+        {
+            int nx = x + offset[dir][0];
+            int ny = y + offset[dir][1];
+            if (canMove(tmp_lab, nx, ny))
+            {
+                tmp_lab[ny][nx] = VISITED;
+                tmpq.push(make_pair(nx, ny));
+            }
+        }
+    }
+
+    // 큐에서 모든 바이러스를 검사한다. 따라서 all_virus를 빼면 기존 virus를 다시 더해야한다.
+    // 따라서 empty의 개수 - 추가한 wall개수 - 모든 virus 수 + 기존 virus 수
+    maxSafe = max(maxSafe, safe - 3 - all_virus + virus);
+}
+
+void dfs(int wall)
+{
+    if (wall == 3)
+    {
+        bfs();
+        return;
+    }
+
+    for (int i = 0; i < n; i++)
+    {
+        for (int j = 0; j < m; j++)
+        {
+            if (lab[i][j] == EMPTY)
+            {
+                lab[i][j] = WALL;
+                dfs(wall + 1);
+                lab[i][j] = EMPTY;
+            }
+        }
+    }
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    cin >> n >> m;
+    lab = vector<vector<int>>(n, vector<int>(m));
+    for (int i = 0; i < n; i++)
+    {
+        for (int j = 0; j < m; j++)
+        {
+            cin >> lab[i][j];
+            if (lab[i][j] == VIRUS)
+            {
+                q.push(make_pair(j, i)); // (x, y) 꼴로 저장
+                virus++;
+            }
+            if (lab[i][j] == EMPTY)
+                safe++;
+        }
+    }
+
+    dfs(0);
+    cout << maxSafe;
+
+    return 0;
+}

g0rnn/README.md

@@ -6,5 +6,6 @@
 | 2차시 | 2024.10.03 |    트리    |   [LCA2](https://school.programmers.co.kr/learn/courses/30/lessons/176963)    | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/7  |
 | 3차시 | 2024.10.04 |   문자열   |             [잃어버린 괄호](https://www.acmicpc.net/problem/1541)             | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/9  |
 | 4차시 | 2024.10.11 | 브루트포스 |              [영화감독 숌](https://www.acmicpc.net/problem/1436)              | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/15 |
+| 5차시 | 2024.11.01 |  BFS/DFS   |                [연구소](https://www.acmicpc.net/problem/14502)                | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/17 |
 
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