福大校赛 G题 小小的悲剧哈

福大校赛 G题 小小的悲剧哈

今天做得还算顺利哈，其他的题都还蛮简单的，就是这道G题，yy了半天，写这个题的时候快米有时间了，最后也没出。 后来听yayamao说用搜索，囧了~完全没想到，我只会用DP，呵呵。代码奉上。

#include < iostream >
#include < cmath >
#include < cstring >
#include < algorithm >
using   namespace  std;


int  dp[ 1010 ][ 10 ];
int  pre[ 1010 ][ 10 ];
char  s[ 1010 ];
int  a[ 1010 ];

int  n;
bool  check()
{
    int i;
    for(i=1;i<=n;i++)
    {
        if(a[i]==0||a[i]==5)
            return true;
    }
    return false;
}

void  init()
{
    memset(dp,-1,sizeof(dp));
    int i;
    for(i=1;i<=n;i++)
        a[i]=s[i]-'0';
}

int  get5()
{

    int i;
    for(i=n;i>=1;i--)
    {
        if(a[i]==5)
            return i;
    }

}


int  get0()
{
    int res=0;
    int i;
    for(i=n;i>=0;i--)
    {
        if(a[i]==0)
            res++;
    }
    return res;
        
}

int  re[ 2000 ];

bool  CheckAllZero( int  n)
{

    int i;
    for(i=1;i<=n;i++)
    {
        if(re[i]!=0)
            return false;
    }
    return true;

}

int  main()
{
    int t;
    int i,j,k;
    scanf("%d",&t);
    while(t--)
    {
        
        scanf("%s",s+1);
        n=strlen(s+1);

        init();
        sort(a+1,a+1+n);
        reverse(a+1,a+1+n);
        if(check()==false)
        {
            printf("impossible\n");
            continue;
        }
        if(a[n]==0)
        {
            dp[0][0]=1;
            for(i=1;i<=n;i++)
            {
                for(j=i-1;j>=0;j--)
                {
                    for(k=9;k>=0;k--)
                    {
                        //if(j==1&&k==7)
                        //    __asm int 3;
                        if(dp[j][k]==1&&dp[j+1][(k+a[i])%9]==-1)
                        {

                            dp[j+1][(k+a[i])%9]=1;
                            pre[j+1][(k+a[i])%9]=a[i];
                        }
                    }
                }
            }
            int f=0;
            int nn;
            for(i=1000;i>=1;i--)
            {
                if(dp[i][0]==1)
                {
                    nn=i;
                    break;
                }
            }


            re[i]=pre[i][0];
            int t1=nn;
            int t2=0;
            for(j=nn-1;j>=1;j--)
            {
                t1--;
                t2=(t2-pre[j+1][t2]+9)%9;
                re[j]=pre[t1][t2];
            }
        
            if(CheckAllZero(nn))
            {
                printf("0\n");
                continue;
            }

            for(i=1;i<=nn;i++)
                printf("%d",re[i]);
            printf("\n");
            
        }

        else
        {
            int t=get5();
            swap(a[t],a[n]);
            sort(a+1,a+n);//这里要少排一个5
            dp[0][0]=1;
            for(i=1;i<n;i++)
            {
                for(j=i-1;j>=0;j--)
                {
                    for(k=9;k>=0;k--)
                    {
                        if(dp[j][k]==1&&dp[j+1][(k+a[i])%9]==-1)
                        {

                            dp[j+1][(k+a[i])%9]=1;
                            pre[j+1][(k+a[i])%9]=a[i];
                        }
                    }
                }
            }
            int f=0;
            int nn;
            for(i=1000;i>=1;i--)
            {

                if(dp[i][0]==1)
                {
                    f=1;
                    nn=i;
                    break;
                }
            }
            if(f==0)
                printf("impossible\n");
            if(f==1)
            {
                re[i]=pre[i][0];
                int t1=nn;
                int t2=0;
                for(j=nn-1;j>=1;j--)
                {
                    t1--;
                    t2=(t2-pre[j+1][t2]+9)%9;
                    re[j]=pre[t1][t2];
                }
            }
            for(i=1;i<=nn;i++)
                printf("%d",re[i]);
            printf("\n");

        }

    }
    return 0;


}

顺带一提，比赛的时候 问了下zjut_DD G题的解法，他没睬我，比赛结束后发现 他就这题没杀出来。。。。


好吧，我只能说DP解法是错的。。。。。。
6596487788
这组数据确实过不去。。。