• Good Bye 2017 G. New Year and Original Order


    G. New Year and Original Order

    time limit per test
    2 seconds
    memory limit per test
    256 megabytes
    input
    standard input
    output
    standard output

    Let S(n) denote the number that represents the digits of n in sorted order. For example, S(1) = 1, S(5) = 5, S(50394) = 3459, S(353535) = 333555.

    Given a number X, compute modulo 109 + 7.

    Input

    The first line of input will contain the integer X (1 ≤ X ≤ 10700).

    Output

    Print a single integer, the answer to the question.

    Examples

    Input

    21

    Output

    195

    Input

    345342

    Output

    390548434

    Note

    The first few values of S are 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 11, 12, 13, 14, 15, 16, 17, 18, 19, 2, 12. The sum of these values is 195.

    tls原话最简单的数位dp,出题人成功骗过验题人放在了G。

    Oh...uuu...原来是简单的数位dp...等等...tls的简单,莫不是.....

    #include<bits/stdc++.h>
    #define LL long long
    using namespace std;
    char s[705];
    int dp[705][705][2],res;
    const int mod=1e9+7;
    int main()
    {
        cin>>s;
        int len=strlen(s);
        int ll,kk,i,j,k,l,m;
        for(i=1;i<=9;i++)
        {
            dp[0][0][1]=1;
            for(j=0;j<len;j++)
                for(k=0;k<=j;k++)
                    for(l=0;l<=1;l++)
                        for(m=0;m<=9;m++)
                        {
                            if(m<s[j]-'0')  ll=0;
                            else if(m==s[j]-'0')    ll=l;
                            else if(l)  continue;
                            else    ll=0;
                            if(m>=i)  kk=k+1;
                            else kk=k;
                            dp[j+1][kk][ll]=(dp[j+1][kk][ll]+dp[j][k][l])%mod;
                        }
            for(j=1,k=1;j<=len;j++)
            {
                res=(res+(LL)k*(dp[len][j][0]+dp[len][j][1]))%mod;
                k=(k*10ll+1)%mod;
            }
            for(j=0;j<=len;j++)
                for(k=0;k<=j;k++)
                    for(l=0;l<=1;l++)
                        dp[j][k][l]=0;
        }
        cout<<res<<endl;
        return 0;
    }
    View Code

    九月巨巨的滚动数组:

    #include<bits/stdc++.h>
    using namespace std;
    const int mod=1e9+7,maxn=710;
    #define LL long long
    LL sum[maxn][2],dp[maxn][2];
    string s;
    inline void Update(LL &x,LL y)
    {
       x=(x+y)%mod;
    }
    void Clear()
    {
        memset(dp,0,sizeof(dp));
        memset(sum,0,sizeof(sum));
        dp[0][0]=1;
    }
    int main()
    {
        cin>>s;
        int len=s.length();
        LL ans=0;
        for(int l=1;l<=9;l++)
        {
            Clear();
            for(int i=0;i<len;i++)
                for(int j=0;j<2;j++)
                    for(int k=0;k<=9;k++)
                    {
                        if(!j&&k>s[i]-'0') continue;
                        Update(dp[i+1][j|k<s[i]-'0'],dp[i][j]);  ///j和k<s[i]  任意一个是1就为1
                        if(k<l) Update(sum[i+1][j|k<s[i]-'0'],sum[i][j]);
                        else Update(sum[i+1][j|k<s[i]-'0'],(sum[i][j]*10+dp[i][j])%mod);
                    }
            Update(ans,sum[len][0]);
            Update(ans,sum[len][1]);
        }
        cout<<ans<<endl;
        return 0;
    }
    View Code
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  • 原文地址:https://www.cnblogs.com/weimeiyuer/p/8214666.html
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