P1879 [USACO06NOV]Corn Fields G

https://www.luogu.com.cn/record/76684822

Luogu/P1879/P1879.cpp

@@ -0,0 +1,57 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 15,
+          M = 0xfff + 5;  // = (11111111111)2 + 5
+const int mod = 1e8;
+
+int m, n, a[N], f[N][M], ans;
+bool s[M];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> m >> n;
+
+    for (int i = 1; i <= m; i++) {
+        for (int j = 1, x; j <= n; j++) {
+            cin >> x;
+            a[i] <<= 1;
+            a[i] += x;
+        }
+    }
+
+    for (int i = 0; i < 0xfff; i++) {
+        // 行内不存在相邻的草地
+        if (!((i << 1) & i) && !((i >> 1) & i)) {
+            s[i] = true;
+        }
+    }
+
+    f[0][0] = 1;
+    for (int i = 1; i <= m; i++) {
+        // 当前行的状态
+        for (int j = 0; j < 0xfff; j++) {
+            // j 是合法的状态，且没有草被种在贫瘠的土地上
+            if (s[j] && (a[i] & j) == j) {
+                // 枚举上一行的状态
+                for (int k = 0; k < 0xfff; k++) {
+                    if (!(k & j)) {  // k 和 j 间不存在相邻的土地
+                        f[i][j] = (f[i][j] + f[i - 1][k]) % mod;
+                    }
+                }
+            }
+        }
+    }
+
+    for (int i = 0; i < 0xfff; i++) {
+        ans = (ans + f[m][i]) % mod;
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}