'commit'

TangDou/AcWing/Dfs/1113_bfs.cpp

@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+const int N = 30;
+struct Node {
+    int x;
+    int y;
+};
+
+char g[N][N];
+int n, m;
+int dx[] = {0, 1, 0, -1};
+int dy[4] = {1, 0, -1, 0};
+bool st[N][N];
+int cnt;
+
+void bfs(int x, int y) {
+    queue<Node> q;
+    q.push({x, y});
+
+    while (q.size()) {
+        Node t = q.front();
+        q.pop();
+        cnt++;
+        for (int i = 0; i < 4; i++) {
+            int tx = t.x + dx[i], ty = t.y + dy[i];
+            if (tx < 0 || tx >= n || ty < 0 || ty >= m) continue;
+            if (st[tx][ty]) continue;
+            if (g[tx][ty] != '.') continue;
+            st[tx][ty] = true;
+            q.push({tx, ty});
+        }
+    }
+}
+
+int main() {
+    while (cin >> m >> n, n || m) {
+        memset(st, 0, sizeof st);
+        cnt = 0;
+
+        int x, y;
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                cin >> g[i][j];
+                if (g[i][j] == '@') x = i, y = j;
+            }
+        }
+        bfs(x, y);
+        printf("%d\n", cnt);
+    }
+    return 0;
+}