UVA11375

题目连接：UVA - 11375

递推+大数

分析参见lij白书p110

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
const int maxn=2010;

class bign
{
public:
    int date[500];
    int len;
    bign(){memset(date,0,sizeof(date));len=1;}
    void operator =(const int &x)
    {
        int temp=x;
        while(temp)
        {
            date[len++]=temp%10;
            temp/=10;
        }
    }
    bign operator + (const bign& a)
    {
        bign temp;
        temp.len=max(len,a.len);
        for(int i=1;i<=temp.len;i++)
        {
            temp.date[i]+=date[i]+a.date[i];
            if(temp.date[i]>=10)
            {
                temp.date[i+1]=temp.date[i+1]+temp.date[i]/10;
                temp.date[i]%=10;
                if(i==temp.len) temp.len++;
            }
        }
        return temp;
    }
    bign operator +=(const bign &a)
    {
        *this=*this+a;
        return *this;
    }
     bign operator +=(const int &a)
    {
        *this=*this+a;
        return *this;
    }
    bign operator+ (const int& a)
    {
        bign temp;
        temp=a;
        temp=*this+temp;
        return temp;
    }
    friend ostream& operator << ( ostream & out,const bign& ans)
    {
        int i=ans.len;
        while(ans.date[i]==0&&i>=1) i--;
        if(i!=0)
            for(;i>=1;i--) out<<ans.date[i];
        else out<<"0";
        return out;
    }
};
bign ans[maxn],d[maxn];
int c[]={6,2,5,5,4,5,6,3,7,6};
int main()
{
    d[0]=1;
    for(int i=0;i<maxn;i++)
        for(int j=0;j<10;j++)
        if(!(i==0&&j==0)&&c[j]+i<maxn)
            d[c[j]+i]+=d[i];
    ans[0]=0;
    for(int i=1;i<maxn;i++)
        ans[i]=ans[i-1]+d[i];
    for(int i=6;i<maxn;i++)
        ans[i]+=1;
    int n;
    while(cin>>n)
        cout<<ans[n]<<endl;
    return 0;
}