#13367. 「NOIP2022模拟赛pb」球场

http://www.nfls.com.cn:10611/submission/244410

NFLSOJ/13367/13367.cpp

@@ -0,0 +1,125 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+
+// using std::cin;
+// using std::cout;
+std::ifstream cin("field.in");
+std::ofstream cout("field.out");
+const char endl = '\n';
+
+const int N = 505,
+          M = (N << 1) * (N << 1);
+
+int h, w, fa[M], x1[M], y1[M], x2[M], y2[M], ans;
+std::string g[N << 1];
+bool flag;
+
+int id(int x, int y) {
+    return (x - 1) * w + y;
+}
+
+int find(int x) {
+    return fa[x] == x ? x : fa[x] = find(fa[x]);
+}
+
+void merge(int x, int y) {
+    x = find(x), y = find(y);
+
+    if (x == y) return;
+
+    flag = true;
+    fa[y] = x;
+
+    x1[x] = std::min(x1[x], x1[y]);
+    y1[x] = std::min(y1[x], y1[y]);
+
+    x2[x] = std::max(x2[x], x2[y]);
+    y2[x] = std::max(y2[x], y2[y]);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> h >> w;
+
+    for (int i = 1; i <= 2 * h + 1; i++) {
+        cin >> g[i];
+
+        g[i] = ' ' + g[i];
+    }
+
+    for (int i = 1; i <= h; i++) {
+        for (int j = 1; j <= w; j++) {
+            int p = id(i, j);
+            fa[p] = p;
+            x1[p] = x2[p] = i;
+            y1[p] = y2[p] = j;
+        }
+    }
+
+    for (int i = 1; i <= h; i++) {
+        for (int j = 1; j < w; j++) {
+            if (g[i * 2][j * 2 + 1] == '.') {
+                merge(id(i, j), id(i, j + 1));
+            }
+        }
+    }
+
+    for (int j = 1; j <= w; j++) {
+        for (int i = 1; i < h; i++) {
+            if (g[i * 2 + 1][j * 2] == '.') {
+                merge(id(i, j), id(i + 1, j));
+            }
+        }
+    }
+
+    while (true) {
+        flag = false;
+
+        for (int i = 1; i <= h; i++) {
+            for (int j = 1; j <= w; j++) {
+                if (x2[find(id(i, j))] > i) {
+                    merge(id(i, j), id(i + 1, j));
+                }
+            }
+        }
+
+        for (int i = h; i >= 1; i--) {
+            for (int j = 1; j <= w; j++) {
+                if (x1[find(id(i, j))] < i) {
+                    merge(id(i, j), id(i - 1, j));
+                }
+            }
+        }
+
+        for (int j = 1; j <= w; j++) {
+            for (int i = 1; i <= h; i++) {
+                if (y2[find(id(i, j))] > j) {
+                    merge(id(i, j), id(i, j + 1));
+                }
+            }
+        }
+
+        for (int j = w; j >= 1; j--) {
+            for (int i = 1; i <= h; i++) {
+                if (y1[find(id(i, j))] < j) {
+                    merge(id(i, j), id(i, j - 1));
+                }
+            }
+        }
+
+        if (!flag) break;
+    }
+
+    for (int i = 1; i <= h; i++) {
+        for (int j = 1; j <= w; j++) {
+            if (find(id(i, j)) == id(i, j)) ans++;
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}