Submission #992878

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;

#define EACH(i,a) for (auto& i : a)
#define FOR(i,a,b) for (ll i=(a);i<(b);i++)
#define RFOR(i,a,b) for (ll i=(b)-1;i>=(a);i--)
#define REP(i,n) for (ll i=0;i<(n);i++)
#define RREP(i,n) for (ll i=(n)-1;i>=0;i--)
#define debug(x) cout<<#x<<": "<<x<<endl
#define pb push_back
#define ALL(a) (a).begin(),(a).end()

const ll linf = 1e18;
const int inf = 1e9;
const double eps = 1e-12;
const double pi = acos(-1);

template<typename T>
istream& operator>>(istream& is, vector<T>& vec) {
    EACH(x,vec) is >> x;
    return is;
}
template<typename T>
ostream& operator<<(ostream& os, vector<T>& vec) {
    REP(i,vec.size()) {
        if (i) os << " ";
        os << vec[i];
    }
    return os;
}
template<typename T>
ostream& operator<<(ostream& os, vector< vector<T> >& vec) {
    REP(i,vec.size()) {
        if (i) os << endl;
        os << vec[i];
    }
    return os;
}
ll maxX = 1e5;
vector<ll> get_divs(ll n) {
    vector<ll> res;
    for (ll i = 1; i*i <= n; ++i) {
        if (n % i == 0) {
            res.pb(i);
            if (i != n/i) res.pb(n/i);
        }
    }
    return res;
}
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    ll N, A; cin >> N >> A;
    vector<ll> dp(maxX+1, linf);
    dp[1] = 0;
    FOR(i, 2, maxX+1) {
        vector<ll> divs = get_divs(i);
        EACH(j, divs) {
            if (j >= i) continue;
            dp[i] = min(dp[i], dp[j] + i/j + A);
        }
    }
    ll ans = linf;
    FOR(i, 1, maxX+1) {
        ans = min(ans, dp[i] + (N+i-1)/i);
    }
    cout << ans << endl;
}

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Judge Result