zju 2852 Deck of Cards

#include < iostream >
using   namespace  std;
int  dp[ 101 ][ 22 ][ 22 ][ 22 ];
// dp[k][r][s][t]表示前k张card里面三堆分别为r点、s点、t点时的最优值
int  MAX( int  x, int  y)
{
    if( x>y )
        return x;
    else
        return y;
}
int  fun( char  ch)
{
    if(ch>='2' && ch<='9')
        return ch-'0';
    if(ch == 'A')
        return 1;
    if(ch == 'F')
        return 11;
    return 10;
}
int  main()
{
    int n,k,r,s,t,maxs,m;
    while(cin>>n && n)
    {
        char a;        
        for(k=1;k<=n;k++)
            for(r=0;r<22;r++)
                for(s=0;s<22;s++)
                    for(t=0;t<22;t++)
                        dp[k][r][s][t] = 0;
        cin>>a;
        m = fun(a);
        if(m == 11)
        {
            dp[1][0][0][0] = 350;
        }
        else
        {
            dp[1][m][0][0] = 50;
            dp[1][0][m][0] = 50;
            dp[1][0][0][m] = 50;
        }
        for(k=2;k<=n;k++)
        {
            cin>>a;
             m = fun(a);
            for(r=0;r<=21;r++)
                for(s=0;s<=21;s++)
                    for(t=0;t<=21;t++)
                    {
                        if(dp[k-1][r][s][t] == 0)
                            continue;
                        if(r + m == 21 || (m == 11 && r < 21 ))//一定要放在前面
                        {                 //r<21 表示还未超过21点
                            //只有能放的情况下才能操作，s，t可以等于21
                            dp[k][0][s][t] = MAX(dp[k][0][s][t],dp[k-1][r][s][t] + 150);
                        }
                        else if(r + m < 21)
                        {
                            dp[k][r+m][s][t] = MAX(dp[k][r+m][s][t],dp[k-1][r][s][t] + 50);
                        }
                        else if(r + m > 21 && r < 21)
                        {
                            dp[k][21][s][t] = MAX(dp[k][21][s][t],dp[k-1][r][s][t] + 50);
                        }

                        if(s + m == 21 || (m == 11 && s < 21))//一定要放在前面
                        {
                            dp[k][r][0][t] = MAX(dp[k][r][0][t],dp[k-1][r][s][t] + 250);
                        }
                        else if(s + m < 21)
                        {
                            dp[k][r][s+m][t] = MAX(dp[k][r][s+m][t],dp[k-1][r][s][t] + 50);
                        }
                        else if(s + m > 21 && s < 21)
                        {
                            dp[k][r][21][t] = MAX(dp[k][r][21][t],dp[k-1][r][s][t] + 50);
                        }

                        if(t + m == 21 || (m == 11 && t < 21))//一定要放在前面
                        {
                            dp[k][r][s][0] = MAX(dp[k][r][s][0],dp[k-1][r][s][t] + 350);
                        }
                        else if(t + m < 21)
                        {
                            dp[k][r][s][t+m] = MAX(dp[k][r][s][t+m],dp[k-1][r][s][t] + 50);
                        }
                        else if(t + m > 21 && t < 21)
                        {
                            dp[k][r][s][21] = MAX(dp[k][r][s][21],dp[k-1][r][s][t] + 50);
                        }
                    }
        }
        maxs = 0;
        for(k=1;k<=n;k++)
            for(r=0;r<22;r++)
                for(s=0;s<22;s++)
                    for(t=0;t<22;t++)
                        if(maxs < dp[k][r][s][t])
                            maxs = dp[k][r][s][t];
        cout<<maxs<<endl;
    }
    return 0;
}