TopCoder SRM 390 SetOfPatterns

自己憋了N久也没思路，看了一下别人的代码，神呀，这就是差距呀，继续努力。

代码：

#include<iostream>
#include<cstring>
#include<cstdio>
#include<string>
#include<set>
#include<map>
#include<cmath>
#include<algorithm>
#include<vector>
#include<cmath>
#include<queue>
#include<stack>

//#define ull unsigned long long
#define ll long long

using namespace std;

const int INF=0x3f3f3f3f;

const int MOD=1000003;
const int N=15;
int dp0[1<<N],dp1[1<<N];
class SetOfPatterns
{
    public:
    int howMany(vector <string> p, int k)
    {
        int n=p.size();
        int m=p[0].size();
        memset(dp0,0,sizeof(dp0));
        dp0[(1<<n)-1]=1;
        for(int i=0;i<m;++i)
        {
            memset(dp1,0,sizeof(dp1));
            for(char c='a';c<='z';++c)
            {
            	int k=0;
                for(int j=0;j<n;++j)
                {
                    if(p[j][i]==c||p[j][i]=='?')
                    k=(k|(1<<j));
                }
                for(int i=0;i<(1<<n);++i)
                {
                    dp1[i&k]=(dp1[i&k]+dp0[i])%MOD;
                }
            }
            memcpy(dp0,dp1,sizeof(dp0));
        }
        int sum=0;
        for(int i=0;i<(1<<n);++i)
        if(__builtin_popcount(i)==k)
        sum=(sum+dp0[i])%MOD;
        return sum;
    }
};