hdu 4597Play Game

#include <cstdio>#include <cstring>int dp[23][23][23][23];int arr[2][23];int max(int x,int y){    return x>y?x:y;}int dfs(int x1,int y1,int x2,int y2){    if(x1>y1&&x2>y2) return 0;    if(dp[x1][y1][x2][y2]) return dp[x1][y1][x2][y2];    int v=0,sum=arr[0][y1]-arr[0][x1-1]+arr[1][y2]-arr[1][x2-1];    if(x1<=y1)    {        v=max(v,sum-dfs(x1+1,y1,x2,y2));        v=max(v,sum-dfs(x1,y1-1,x2,y2));    }    if(x2<=y2)    {        v=max(v,sum-dfs(x1,y1,x2+1,y2));        v=max(v,sum-dfs(x1,y1,x2,y2-1));    }    return dp[x1][y1][x2][y2]=v;}int main(){//    freopen("in.txt","r",stdin);    int t,n,x;    scanf("%d",&t);    while(t--)    {        scanf("%d",&n);        arr[0][0]=arr[1][0]=0;        for(int i=0; i<2; ++i)            for(int j=1; j<=n; ++j)            {                scanf("%d",&x);                arr[i][j]=x+arr[i][j-1];            }        memset(dp,0,sizeof(dp));        printf("%d\n",dfs(1,n,1,n));    }    return 0;}