一时暴搜一时爽 一直暴搜一直爽 cxl居然和我写的同款dfs，天呢
菜鸡开始对这题并没有什么想法 状态方程死活想不出来 还是暴搜好
1 #include<bits/stdc++.h> 2 using namespace std; 3 #define ll long long 4 #define rg register 5 const int N=200,K=100,P=9901; 6 int n,k,f[K+5][N+5],ans=0; 7 template <class t>void rd(t &x) 8 { 9 x=0;int w=0;char ch=0; 10 while(!isdigit(ch)) w|=ch=='-',ch=getchar(); 11 while(isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=getchar(); 12 x=w?-x:x; 13 } 14 15 void dfs(int deep,int l,int r) 16 { 17 if(deep==k&&(l+r+1)==n) {++ans;ans%=P;return;} 18 if((l+r+1>=(1<<deep))||deep>k) return; 19 dfs(deep+1,l,r+2);dfs(deep+1,l+2,r); 20 dfs(deep,l+2,r);dfs(deep,l,r+2); 21 } 22 23 int main() 24 { 25 freopen("nocows.in","r",stdin); 26 freopen("nocows.out","w",stdout); 27 rd(n),rd(k); 28 if(n==(1<<k)-1) {printf("1");exit(0);} 29 dfs(2,1,1); 30 printf("%d",ans); 31 return 0; 32 }