2014.12.13模拟赛【准考证号】

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<ctime>
#define LL long long
#define inf 0x7ffffff
#define pa pair<int,int>
#define pi 3.1415926535897932384626433832795028841971
using namespace std;
inline LL read()
{
    LL x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
int f[20][10];
LL a,b;
LL sec[20];
inline void pre()
{
	sec[0]=1;for (int i=1;i<=15;i++)sec[i]=sec[i-1]*10;
	f[1][4]=1;
	for (int i=2;i<=12;i++)
	{
		for (int j=0;j<=9;j++)
		{
		  for (int k=0;k<=9;k++)
		    f[i][j]+=f[i-1][k];
		}
		f[i][3]+=sec[i-2]-f[i-1][7];
		f[i][4]=sec[i-1];
	}
}
inline LL calc(LL x)
{
	if (x<1)return 0;
	int dig[20]={0},len=0;
	LL tot=0,dat=x;
	while (x)
	{
		dig[++len]=x%10;
		x/=10;
	}
	while (len)
	{
		for (int i=0;i<dig[len];i++)tot+=(LL)f[len][i];
		if (dig[len]==4)
		{
			tot+=(LL)dat%sec[len-1]+1;
			break;
		}
		if (dig[len+1]==3&&dig[len]==7)
		{
			tot+=(LL)dat%sec[len-1]+1;
			break;
		}
		if (dig[len+1]==3&&dig[len]>7)
		{
			tot-=(LL)f[len][7];
			tot+=sec[len-1];
		}
		len--;               
	}
	return dat-tot;
}
int main()
{
	freopen("ticket.in","r",stdin);
	freopen("ticket.out","w",stdout);
	pre();
	a=read();b=read();
	printf("%d\n",calc(b)-calc(a-1));
	return 0;
}