Submission #1629226

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Source Code Expand

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define MOD 1000000007
#define rep(i,n) for(i=0;i<n;i++)
#define loop(i,a,n) for(i=a;i<n;i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

typedef vector<int> vi;
typedef pair<int,int> pii;

int i,j,k;


ll solve(int n, string s){

  ll dp[20][2][2]={};
  dp[0][0][0]=1;

  rep(i,n)rep(j,2)rep(k,2){
    int lim=j?9:s[i]-'0',d;
    rep(d,lim+1)
      dp[i+1][j||d<lim][k||d==4||d==9]+=dp[i][j][k];
  }

  ll ret=0;
  rep(j,2)ret+=dp[n][j][1];

  return ret;
}

int main(void) {
  ll a,b;
  cin>>a>>b;
  string s=to_string(a-1);
  string t=to_string(b);
  cout<<solve((int)t.size(),t)-solve((int)s.size(),s)<<endl;
}

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