Submission #29119657

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Source Code Expand

#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
// using mint = modint1000000007;
#include <bits/stdc++.h>
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define rep2(i,k,n) for (int i = (k); i < (n); ++i)
using namespace std;
using ll = long long;
// using P = pair<ll,ll>;
using P = pair<int,int>;
using vint = vector<int>;
using vll = vector<ll>;
using vvint = vector<vector<int>>;
using vvll = vector<vector<ll>>;

// const ll INF = (ll)2e18+9;
const int INF = (int)2e9+7;
// const ll MOD = (ll)1e9+9;
template<typename T>
void chmin(T &a, T b) { a = min(a, b); }
template<typename T>
void chmax(T &a, T b) { a = max(a, b); }

template<typename T>
void print(vector<T> v) {
    int n = v.size();
    rep(i,n) {
        if (i == 0) cout << v[i];
        else cout << ' ' << v[i];
    }
    cout << endl;
}

mint sum(ll x) {
    return mint(x+1) * x / 2;
}

void solve() {
    ll n;
    cin >> n;

    ll l = 1;
    mint ans = 0;
    while (l <= n) {
        ll r = min(n+1, 10*l);
        ll len = r-l;
        ans += sum(len);
        l *= 10;
    }
    cout << ans.val() << endl;
}

int main() {
    solve();
    return 0;
}

Submission Info

Judge Result