POJ 1185 炮兵阵地 状压dp

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

int n, m, cnt, size;
int a[110], st[70], ct[70];
char str[15];
int f[110][70][70];
void init()
{
size = 0;
int maxn = 1 << m;
for (int i = 0; i < maxn; i++){
if (!(i&(i<<2)) && !(i&(i<<1))){
st[size] = i;
ct[size] = 0;
int tmp = i;
while(tmp) tmp = tmp&(tmp-1), ct[size]++;
size++;
}
}
}
int main()
{
scanf("%d %d", &n, &m);
for (int i = 1; i <= n; i++){
scanf("%s", str);
a[i] = 0;
for (int j = 0; j < m; j++){
if (str[j] == 'H') a[i] |= 1 << j;
}
}
init();
memset(f, 0, sizeof(f));
for (int j = 0; j < size; j++){
if (!(a[1]&st[j])) f[1][j][0] = ct[j];
}
for (int i = 2; i <= n; i++){
for (int j = 0; j < size; j++){
if (a[i]&st[j]) continue;
for (int k = 0; k < size; k++){
if (a[i-1]&st[k]) continue;
if (i == 2){
if (!(st[j]&st[k]))
f[i][j][k] = max(f[i][j][k], f[i-1][k][0] + ct[j]);
}
else for (int l = 0; l < size; l++){
if (!(a[i-2]&st[l]) && !(st[j]&st[k]) && !(st[j]&st[l]) && !(st[k]&st[l]))
f[i][j][k] = max(f[i][j][k], f[i-1][k][l] + ct[j]);
}
}
}
}
int ans = 0;
for (int j = 0; j < size; j++)
for (int k = 0; k < size; k++)
ans = max(ans, f
[j][k]);
printf("%d\n", ans);
return 0;
}