hdu4301 状态dp

#include <iostream>#include <cstring>#include <cstdio>#include <math.h>#include <cstdlib>#include <queue>#include <algorithm>using namespace std;#define N 1050#define mod 100000007int dp[N][N*2][2];int main (){memset(dp,0,sizeof(dp));dp[1][1][0]=1;dp[1][2][1]=1;for(int i=1;i<=1000;++i){for(int j=1;j<=2*i;++j){dp[i+1][j][0]=(dp[i+1][j][0]+dp[i][j][0]+2*dp[i][j][1])%mod;dp[i+1][j+1][0]=(dp[i+1][j+1][0]+dp[i][j][1]+dp[i][j][0])%mod;dp[i+1][j][1]=(dp[i+1][j][1]+dp[i][j][1])%mod;dp[i+1][j+1][1]=(dp[i+1][j+1][1]+2*dp[i][j][0]+2*dp[i][j][1])%mod;dp[i+1][j+2][1]=(dp[i+1][j+2][1]+dp[i][j][0]+dp[i][j][1])%mod;}}int n,k;int t;scanf("%d",&t);while(t--){scanf("%d%d",&n,&k);printf("%d\n",(dp[n][k][0]+dp[n][k][1])%mod);}return 0;}