POJ-1185 炮兵阵地(状态压缩DP)

 1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstdlib>
 4 #include <cstring>
 5 #include <iostream>
 6 #include <algorithm>
 7 using namespace std;
 8 typedef long long LL;
 9 const int MAX=101;
10 int n,m,num;
11 int f[MAX][(1<<10)][(1<<10)];
12 int s[1030],c[1030];
13 int allow[1030];
14 bool ok(int x){    if ((x&(x<<1)) || (x&(x<<2))) return false;    return true;}
15 int getnum(int x){ int an=0; while (x){ an+=x%2;x/=2;} return an;}
16 bool fit(int x,int y){return ((allow[x]&y)?false:true);}
17 void init(){
18     int i,j;
19     char cc;
20     scanf("%d%d\n",&n,&m);
21     memset(allow,0,sizeof(allow));
22     for (i=1;i<=n;i++){
23         for (j=1;j<=m;j++){
24             cc=getchar();
25             if (cc==‘H‘){
26                 allow[i]+=(1<<(m-j));
27             }
28         }
29         getchar();
30     }
31     for (i=0;i<(1<<m);i++){
32         if (ok(i)){
33             s[++num]=i;
34             c[num]=getnum(i);
35         }
36     }
37     memset(f,0,sizeof(f));
38     for (i=1;i<=num;i++){
39         if (fit(1,s[i])){
40             f[1][s[i]][0]=c[i];
41         }
42     }
43 }
44 int main(){
45     freopen ("cannon.in","r",stdin);
46     freopen ("cannon.out","w",stdout);
47     int i,j,k,l,ans=0;
48     init();
49     for (i=2;i<=n;i++){
50         for (j=1;j<=num;j++){
51             if (fit(i,s[j])){    
52                 for (k=1;k<=num;k++){
53                     if (fit(i-1,s[k]) && !(s[j]&s[k])){
54                         for (l=1;l<=num;l++){
55                             if (fit(i-2,s[l]) && !(s[l]&s[j]) && !(s[l]&s[k])){
56                                 f[i][s[j]][s[k]]=max(f[i][s[j]][s[k]],f[i-1][s[k]][s[l]]+c[j]);
57                             }
58                         }
59                     }
60                 }
61             }
62         }
63     }
64     for (i=1;i<=num;i++){
65         for (j=1;j<=num;j++){
66             ans=max(ans,f[n][s[i]][s[j]]);
67         }
68     }
69     printf("%d",ans);
70     return 0;
71 }