题目：点击打开链接

题意：一个细胞自动机包含n个格子，每个格子的值都会变成它距离不超过d的所有格子的值，求最后的结果

思路：这个是循环矩阵，可以用O(n^2)的时间过掉

#include 
  
   
#include 
   
     #include 
    
      #include 
     
       using namespace std; typedef long long ll; const int maxn = 505; int n, m, d, k; ll ans[maxn], matrix[maxn]; ll c[maxn+5]; void mul(ll a[], ll b[]) { memset(c, 0, sizeof(c)); for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) c[i] += a[j] * b[(i-j+n) % n]; for (int i = 0; i < n; i++) b[i] = c[i] % m; } int main() { while (scanf("%d%d%d%d", &n, &m, &d, &k) != EOF) { memset(ans, 0, sizeof(ans)); memset(matrix, 0, sizeof(matrix)); for (int i = 0; i < n; i++) cin>>ans[i]; matrix[0] = 1; for (int i = 1; i <= d; i++) matrix[i] = matrix[n - i] = 1; while (k) { if (k & 1) mul(matrix, ans); mul(matrix, matrix); k >>= 1; } for (int i = 0; i < n - 1; i++) printf("%lld ", ans[i]); printf("%lld\n", ans[n-1]); } return 0; }