new file: P1896.cpp

P1896.cpp

@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+#define int long long
+using namespace std;
+int n, kk;
+int dp[15][1100][100];
+int check(int j)
+{
+    if (((j << 1) | (j >> 1)) & j)
+        return -1;
+    return __builtin_popcount(j);
+}
+bool check(int a, int b)
+{
+    return (check(a) == -1 || check(b) == -1) ? 0 : !((a << 1 | a >> 1 | a) & b);
+}
+signed main()
+{
+    scanf("%lld%lld", &n, &kk);
+    dp[0][0][0] = 1;
+    for (int i = 1; i <= n; ++i)
+    {
+        for (int j = 0; j < (1 << n); j++)
+        {
+            int cou = check(j);
+            if (cou != -1)
+            {
+                for (int jj = 0; jj < (1 << n); jj++)
+                {
+                    if (check(j, jj))
+                    {
+                        for (int k = cou; k <= kk; ++k)
+                        {
+                            dp[i][j][k] += dp[i - 1][jj][k - cou];
+                        }
+                    }
+                }
+            }
+        }
+    }
+    int anss = 0;
+    for (int j = 0; j < (1 << n); j++)
+        anss += dp[n][j][kk];
+    printf("%lld\n", anss);
+    return 0;
+}