1 //#pragma comment(linker, "/STACK:167772160")//手动扩栈~~~~hdu 用c++交
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <iostream>
 6 #include <queue>
 7 #include <stack>
 8 #include <cmath>
 9 #include <set>
10 #include <algorithm>
11 #include <vector>
12 // #include<malloc.h>
13 using namespace std;
14 #define clc(a,b) memset(a,b,sizeof(a))
15 #define LL long long
16 const int inf = 0x3f3f3f3f;
17 const double eps = 1e-5;
18 // const double pi = acos(-1);
19 const LL MOD = 1e8;
20 const int N=1<<13;
21 // const LL p = 1e9+7;
22 // inline int r(){
23 //     int x=0,f=1;char ch=getchar();
24 //     while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
25 //     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
26 //     return x*f;
27 // }
28
29 int main() {
30     int n;
31     LL f[20]={0};
32     scanf("%d",&n);
33     f[0]=1;f[1]=1;
34     for(int i=2;i<=n;i++)
35        for(int j=0;j<i;j++)
36           f[i]+=f[j]*f[i-j-1];
37     printf("%I64d\n",f[n]);
38     return 0;
39 }

 1 /**************************************************************
 2     Problem: 3907
 3     User: Tunix
 4     Language: C++
 5     Result: Accepted
 6     Time:84 ms
 7     Memory:944 kb
 8 ****************************************************************/
 9
10 #include<cstdio>
11 #include<cstring>
12
13 typedef long long LL;
14
15 const int N=10001;
16 const LL mod=100000000;
17
18 int tot=0,x[N],p[N],v[N]={0};
19 LL a[1000],b[1000];
20
21 LL pow(LL x,int p) {
22     LL t=1;for (;p;p>>=1,x*=x) if (p&1) t*=x;return t;
23 }
24
25 void mul(LL a[],LL y) {
26     LL x=0,&l=a[0];
27     for (int i=1;i<=l;i++) {
28         a[i]=a[i]*y+x;
29         x=a[i]/mod;
30         a[i]%=mod;
31     }
32     while (x) a[++l]=x%mod,x/=mod;
33 }
34
35 void dec(LL a[],LL b[]) {
36     LL &l=a[0];
37     for (int i=1;i<=l;i++) {
38         if (a[i]<b[i]) a[i+1]--,a[i]+=mod;
39         a[i]-=b[i];
40     }
41     while (!a[l]) l--;
42 }
43
44 void getc(LL a[],int n,int m) {
45     memset(x,0,sizeof x);
46     for (int i=2;i<=n;i++) x[i]++;
47     for (int i=2;i<=m;i++) x[i]--;
48     for (int i=2;i<=n-m;i++) x[i]--;
49     for (int i=n;i>=2;i--)
50     if (!v[i]) mul(a,pow(i,x[i]));
51     else x[v[i]]+=x[i],x[i/v[i]]+=x[i];
52 }
53
54 void print(LL a[]) {
55     int l=a[0];
56     printf("%lld",a[l]);
57     for (int i=l-1;i>=1;i--) printf("%08lld",a[i]);
58     printf("\n");
59 }
60
61 int main() {
62     int n,m;
63     scanf("%d%d",&n,&m);
64     for (int i=2;i<=n+m;i++) {
65         if (!v[i]) p[++tot]=i;
66         for (int j=1,k;j<=tot,(k=p[j]*i)<=n+m;j++) {
67             v[k]=p[j];
68             if (i%p[j]==0) break;
69         }
70     }
71     a[0]=a[1]=b[0]=b[1]=1;
72     getc(a,n+m,n);
73     getc(b,n+m,n+1);
74     dec(a,b);
75     print(a);
76     return 0;
77 }