HDU 4489 The King’s Ups and Downs

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<cstdio>
 5 #include<sstream>
 6 #include<vector>
 7 #include<stack>
 8 #include<queue>
 9 #include<cmath>
10 #include<map>
11 #include<set>
12 using namespace std;
13 typedef long long ll;
14 typedef pair<int,int> pll;
15 const int INF = 0x3f3f3f3f;
16 const int maxn = 1e5 + 5;
17 
18 int n;
19 
20 int c[25][25];
21 ll d[maxn][2];
22 ll sum[maxn];
23 
24 void dp()
25 {
26     memset(c,0,sizeof(c));
27     memset(d,0,sizeof(d));
28 
29     for(int i=0;i<=20;i++)
30     {
31         c[i][0]=1;
32         for(int j=1;j<=i;j++)
33             c[i][j]=c[i-1][j-1]+c[i-1][j];
34     }
35 
36     sum[1]=1;
37     sum[2]=2;
38     d[0][0]=d[0][1]=1;
39     d[1][0]=d[1][1]=1;
40     d[2][0]=d[2][1]=1;
41 
42     for(int i=3;i<=20;i++)
43     {
44         sum[i]=0;
45         for(int j=0;j<=i;j++)
46         {
47             sum[i]+=d[j][0]*d[i-j-1][1]*c[i-1][j];
48         }
49         d[i][0]=d[i][1]=sum[i]/2;
50     }
51 }
52 
53 int main()
54 {
55     //freopen("in.txt","r",stdin);
56     int T;
57     int kase;
58     scanf("%d",&T);
59     dp();
60     while(T--)
61     {
62         scanf("%d%d",&kase, &n);
63         printf("%d %lld\n",kase,sum[n]);
64     }
65     return 0;
66 }