Submission #489721

#	Time	Username	Problem	Language	Result	Execution time	Memory
489721		JerryLiu06	City (BOI06_city)	C++17	100 / 100	5 ms	460 KiB

city

// https://oj.uz/problem/view/BOI06_city

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(0);
 
#define mp make_pair
#define f first
#define s second
 
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert 
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
 
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
 
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
 
template<class T> void remDup(vector<T>& v) { sor(v); v.erase(unique(all(v)), v.end()); }
 
const int MOD = 1e9 + 7;
const int MX = 2e4 + 10;
const ll INF = 1e18;

ll N; int T, K; int C[MX];

ll sum1(ll x) {
    return x * (x + 1) / 2;
}
ll sum2(ll x) {
    return x * (x + 1) * (2 * x + 1) / 6;
}
pl workersCost(ll maxCost) {
    ll numWorkers = 0;
    ll totCost = 0;

    F0R(i, K) {
        ll diff = maxCost - C[i];

        if (diff < 0) {
            break;
        }
        diff /= T;

        ll curWorkers = 4 * sum1(diff + 1);
        ll totDist = 4 * (sum2(diff) + sum1(diff));
        
        totCost += T * totDist + C[i] * curWorkers;
        
        numWorkers += curWorkers;
      
      	if (numWorkers >= N) {
            return {numWorkers, totCost};
        }
    }
    return {numWorkers, totCost};
}

int main() {
    FASTIO;

    cin >> N >> T >> K;

    F0R(i, K) {
        cin >> C[i];
    }
    ll high = 1;

    while (workersCost(high).f < N) {
        high *= 2;
    }
    ll low = 0; ll res = -1;

    while (low <= high) {
        ll mid = (low + high) / 2;

        if (workersCost(mid).f < N) {
            res = mid; low = mid + 1;
        }
        else {
            high = mid - 1;
        }
    }
    pl cur = workersCost(res);

    cout << cur.s + (N - cur.f) * (res + 1) << "\n";
}

• Subtask 1: 100 / 100