Submission #1769967

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;

#define int long long

typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>void chmax(T &t,U f){if(t<f)t=f;}

string i2s(int a){
    stringstream ss;
    ss<<a;
    return ss.str();
}
string S;
int memo[22][2];

int dfs(int n,int f){
    if(n==S.size())return 1;
    int &ret=memo[n][f];

    ret=0;
    rep(i,10){
        if(!f&&i>S[n]-'0')continue;
        if(i==4||i==9)continue;
        ret+=dfs(n+1,f||(i<S[n]-'0'));
    }
    return ret;
}

signed main(){
    int a,b;
    cin>>a>>b;
    a--;

    memset(memo,-1,sizeof(memo));
    S=i2s(b);
    int ret=dfs(0,0);

    memset(memo,-1,sizeof(memo));
    S=i2s(a);
    ret-=dfs(0,0);

    cout<<b-a-ret<<endl;
}

Submission Info

Judge Result