蓝桥杯刷题--（3.24）

Persistence 2023-03-24 23:16:09

小蓝与钥匙

#include <iostream>
using namespace std;
typedef long long LL;
LL C(int a,int b)
{
  LL k=1;
  for (int i = 1; i <= b; i++) {
        k = k * (a - i + 1) / i;
    }
  return k;
}
int main()
{
  LL a[100]={0,0,1};
  for(int i=3;i<=14;i++)
   {
     a[i]=(i-1)*(a[i-1]+a[i-2]);
   }
   cout<<C(28,14)*a[14];
  return 0;
}

https://www.lanqiao.cn/problems/2167/learning/?page=6&first_category_id=1&sort=students_count&tags=2022

李白打酒加强版

#include <iostream>
using namespace std;
typedef long long LL;
const int N=210,mod=1000000007;
LL dp[N][N][N];
int main()
{
  int n,m;
  cin>>n>>m;
  dp[0][0][2]=1;
  for(int i=0;i<=n;i++)
  for(int j=0;j<=m;j++)
  for(int k=0;k<=m;k++)
  {
    LL &v=dp[i][j][k];
    if(i-1>=0&&k%2==0) v=(v+dp[i-1][j][k/2])%mod;
    if(j) v=(v+dp[i][j-1][k+1])%mod;
  }
  cout<<dp[n][m-1][1]%mod;
  return 0;
}