【codevs 2451】互不侵犯king 状压dp

[code]#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
const int MAXN = 1 << 11;
long long dp[12][MAXN][100];
int n,king;
int get_k(int x)
{
    int ans = 0;
    for(int i = n;i >= 1;i --)
        if(x & (1 << i))
            ans ++;
    return ans;
}
void print(int x)
{
    for(int i = n;i >= 1;i --)
        cout<<( (x >> i) & 1);
    cout<<" ";
}
bool cannot(int x)
{
    return (x & (x << 1)) && (x & (x >> 1));
}
void dpdpd()
{
    for(int i = 0;i < (1 << (n + 1));i ++)
            dp[1][i][get_k(i)] = 1;
    for(int i = 2;i <= n;i ++)
    {
        for(int l = 0;l < (1 << (n + 1));l ++)
        {
            if(cannot(l)) continue;
            for(int j = 0;j < (1 << (n + 1));j ++)
            {
                int us = get_k(j);
                if(cannot(j)) continue;
                if(!(l & 1) && !(j & 1) && !(j & l) && !(j & (l << 1)) && !(j & (l >> 1)))
                {
                    for(int k = 0;k <= king - us;k ++)
                    {
                        dp[i][j][k + us] += dp[i - 1][l][k];
                    //  print(l);print(j);printf("%d %d %d %d\n",i,dp[i-1][l][k],dp[i][j][k+us],k+us);puts("");
                    }
                }
            }
        }
    }
    return;
}
int main()
{
    scanf("%d %d",&n,&king);
    dpdpd();
    long long ans = 0;
    for(int i = 0;i < (1 << (n + 1));i ++)
        ans += dp
[i][king];
    printf("%lld\n",ans);
    return 0;
}