BZOJ 1087: [SCOI2005]互不侵犯King

 1 /*Author:WNJXYK*/
 2 #include<cstdio>
 3 using namespace std;
 4 
 5 const int MaxB=10;
 6 int Pow[MaxB+10];
 7 int FullPow;
 8 
 9 inline void init(int x){
10     Pow[0]=1;
11     for (int i=1;i<x;i++) Pow[i]=Pow[i-1]<<1;
12     for (int i=0;i<x;i++) FullPow+=Pow[i];
13 }
14 
15 inline int lowbit(int x){
16     return x&-x;
17 }
18 
19 inline int getDigs(int num){
20     int res=0;
21     while(lowbit(num)!=0){
22         res++;
23         num-=lowbit(num);
24     }
25     return res;
26 }
27 
28 inline bool check(int num){
29     int l=lowbit(num);
30     num-=l;
31     while(lowbit(num)!=0){
32         if (lowbit(num)>>1==l) return false;
33         l=lowbit(num);num-=l;
34     }
35     return true;
36 }
37 
38 const int Maxs=1<<10;
39 const int Maxn=9;
40 const int Maxk=Maxn*Maxn;
41 long long f[Maxn+5][Maxk+5][Maxs+5];
42 
43 int N,K;
44 int main(){
45     //freopen("In.txt","w",stdout);
46     scanf("%d%d",&N,&K);
47     init(N);
48     //printf("%d\n",getDigs(0));
49     for (int sta=0;sta<=FullPow;sta++) if (check(sta))f[1][getDigs(sta)][sta]=1;
50     for (int l=2;l<=N;l++){
51         for (int prev=0;prev<=FullPow;prev++){
52             for (int nxt=0;nxt<=FullPow;nxt++){
53                 if (!(nxt&prev) && !((nxt<<1)&prev) && !((nxt>>1)&prev) && check(nxt)){
54                     for (int k=getDigs(prev);k<=K;k++){
55                         if (k+getDigs(nxt)<=K){
56                             f[l][k+getDigs(nxt)][nxt]+=f[l-1][k][prev];
57                         }
58                     }
59                 }
60             }
61         }        
62     } 
63     /*
64     for (int l=1;l<=N;l++){
65         for (int sta=0;sta<=FullPow;sta++){
66             for (int k=1;k<=K;k++){
67                 if (f[l][k][sta]) printf("%d %d %d -> %d\n",l,sta,k,f[l][k][sta]);
68             }
69         }
70     }
71     printf("\n");
72     for (int i=0;i<=FullPow;i++)printf("%d %d %d -> %d\n",N,i,K,f[N][K][i]);*/
73     long long Ans=0;
74         for (int sta=0;sta<=FullPow;sta++){
75             Ans+=f[N][K][sta];
76         }
77     printf("%lld\n",Ans);
78     return 0;
79 }