Submission #3775230

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Source Code Expand

#include "bits/stdc++.h"
#include <iostream>
#include <string.h>
#include <stdio.h>
#include <map>
#include <vector>
#include <math.h>
#include <algorithm>
#include <queue>
#include <set>
#include <tuple>
using namespace std;

#define FOR(i,init,a) for(int i=init; i<a; i++)
#define rep(i,a) FOR(i,0,a)
#define rrep(i,a) for(int i=a; i>=0; i--)
#define rep1(i,a) for(int i=1; i<=a; i++)
#define cout1(a) cout << a << endl;
#define cout2(a,b) cout << a << " " << b << endl;
#define cout3(a,b,c) cout << a << " " << b << " " << c << endl;
#define cout4(a,b,c,d) cout << a << " " << b << " " << c << " " << d << endl;
#define mem(a,n) memset( a, n, sizeof(a))
#define all(a) a.begin(),a.end()
#define chmin(a,b) a=min(a,b);
#define chmax(a,b) a=max(a,b);

typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef vector<int> V;
typedef vector<V> VV;
typedef vector<VV> VVV;
const int INF = 1e9;
const int MOD = 1e9+7;
const ll LLINF = 1e18;
static const double pi = 3.141592653589793;

ll dp[20][2][2];

ll calc(ll x){
    string s=to_string(x);
    int n=s.size();
    mem(dp,0);
    dp[0][0][0]=1;
    rep(i,n)rep(j,2)rep(k,2){
        if(dp[i][j][k]==0) continue;
        int lim=(j?9:s[i]-'0');
        rep(num,lim+1){
            dp[i+1][j||num<lim][k||num==4||num==9] += dp[i][j][k];
        }
    }
    ll res=dp[n][0][1]+dp[n][1][1];
    return res;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    ll a,b;
    cin>>a>>b;
    
    cout1(calc(b)-calc(a-1))
}

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