abc29d_full.cpp

#include <bits/stdc++.h>
#include <X11/Intrinsic.h>
#include <iostream>
#include <string>
 
using namespace std;
 
#define all(c) ((c).begin()), ((c).end())
#define dump(c) cerr << "> " << #c << " = " << (c) << endl;
#define iter(c) __typeof((c).begin())
#define tr(i, c) for (iter(c) i = (c).begin(); i != (c).end(); i++)
#define REP(i, a, b) for (int i = a; i < (int)(b); i++)
#define rep(i, n) REP(i, 0, n)
#define mp make_pair
#define fst first
#define snd second
#define pb push_back
 
 
 
typedef unsigned int uint;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1 << 29;
const double EPS = 1e-10;
 
template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
 
template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
 
template<class T>
ll stoi(T &str){
    ll ret;
    stringstream ss;
    ss << str;
    ss >> ret;
    return ret;
}
 
template<class T>
string toString(T i) {
    stringstream ss;
    ss << i;
    return ss.str();
}
 
struct prepare {
    prepare() {
        cout.setf(ios::fixed, ios::floatfield);
        cout.precision(8);
        ios_base::sync_with_stdio(false);
    }
} _prepare;
 
 
ll getNumOb1Str(ll num){
    ll counter=0;
    string str=toString(num);
    for(int i=0;i<str.size();i++){
        if(str.at(i)=='1')counter++;
    }
    return counter;
}
 
template<class T>
T getNumOb1(T num){
    T counter=0;
    for(T i=1;i<=num;i++){
        counter+=getNumOb1Str(i);
    }
    return counter;
}
 
template<class T>
T power(T x,T y){
    int res=1;
    for(T i=0;i<y;i++){
        res*=x;
    }
    return res;
}
 
 
ll to[10];
ll perOne[10];
 
void prep(string &str){
    //0-10^i　までカウントしたときに現れる1の数
    to[0]=0;
    to[1]=1;
    REP(i,2,str.size())to[i]=to[i-1]*10+power(10,i-1);
 
    //ll perOne[10];
    perOne[0]=0;
    perOne[1]=1;
    REP(i,2,str.size())perOne[i]=perOne[i-1]*10+power(10,i-1);
}
 
ll getNumFast(string str){
    ll res=0;
    if(str.size()==0)return 0;
    int val = str.at(0) - '0';
    res += to[str.size() - 1]
           + perOne[str.size() - 1] * (val - 1);
    if (val > 1) {
        res += power(10, (int)str.size() - 1);
    } else if (val == 1) {
        string sub = str.substr(1);
        if (sub.size() != 0) {
            res += stoi(sub)+1;
        } else {
            res += 1;
        }
    }
    res+=getNumFast(str.substr(1));
    return res;
}
 
 
 
int main() {
    string s;
    cin>>s;
    prep(s);
  //  ll i=stoi(s);
    ll ans=getNumFast(s);
    cout<<ans<<endl;
    return 0;
}