'commit'

TangDou/AcWing/Dfs/1112_bfs_bool.cpp

@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+using namespace std;
+struct Node {
+    int x;
+    int y;
+    int step;
+};
+const int N = 110;
+int dx[] = {-1, 0, 1, 0};
+int dy[] = {0, 1, 0, -1};
+char g[N][N];
+bool st[N][N];
+int n;
+int xa, ya, xb, yb; // 不能使用x1,y1这样的变量名，可能是万能头中有重复声明
+bool flag;
+void bfs() {
+    flag = false;
+    if (g[xa][ya] == '#') return;
+    if (g[xb][yb] == '#') return;
+    memset(st, 0, sizeof st);
+
+    if (xa == xb && ya == yb) {
+        flag = true;
+        return;
+    }
+
+    queue<Node> q;
+    q.push({xa, ya, 0});
+    st[xa][ya] = true;
+
+    while (q.size()) {
+        auto t = q.front();
+        q.pop();
+        for (int i = 0; i < 4; i++) {
+            int x = t.x + dx[i], y = t.y + dy[i];
+            if (x < 0 || x >= n || y < 0 || y >= n) continue;
+            if (st[x][y]) continue;
+            if (g[x][y] == '#') continue;
+            if (x == xb && y == yb) {
+                flag = true;
+                return;
+            }
+            q.push({x, y, t.step + 1});
+            st[x][y] = true;
+        }
+    }
+}
+int main() {
+    int T;
+    cin >> T;
+    while (T--) {
+        cin >> n;
+        for (int i = 0; i < n; i++) cin >> g[i];
+
+        cin >> xa >> ya >> xb >> yb;
+        bfs();
+        if (flag)
+            cout << "YES" << endl;
+        else
+            cout << "NO" << endl;
+    }
+    return 0;
+}