Submission #389138

#	Time	Username	Problem	Language	Result	Execution time	Memory
389138		solaimanope	Potatoes and fertilizers (LMIO19_bulves)	C++17	100 / 100	462 ms	16640 KiB

bulves

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


/**
 * @brief Slope-Trick
 * @see https://maspypy.com/slope-trick-1-%E8%A7%A3%E8%AA%AC%E7%B7%A8
 */
template< typename T >
struct SlopeTrick {

    const T INF = numeric_limits< T >::max() / 3;

    T min_f;
    priority_queue< T, vector< T >, less<> > L;
    priority_queue< T, vector< T >, greater<> > R;
    T add_l, add_r;


private:
    void push_R(const T &a) {
        R.push(a - add_r);
    }

    T top_R() const {
        return R.top() + add_r;
    }

    T pop_R() {
        T val = top_R();
        R.pop();
        return val;
    }

    void push_L(const T &a) {
        L.push(a - add_l);
    }

    T top_L() const {
        return L.top() + add_l;
    }

    T pop_L() {
        T val = top_L();
        L.pop();
        return val;
    }

public:
    SlopeTrick() : min_f(0), add_l(0), add_r(0) {
        L.push(-INF);
        R.push(INF);
    }

    struct Query {
        T lx, rx, min_f;
    };

    // return min f(x)
    Query query() const {
        return (Query) {top_L(), top_R(), min_f};
    }

    // f(x) += a
    void add_all(const T &a) {
        min_f += a;
    }

    // add \_
    // f(x) += max(a - x, 0)
    void add_a_minus_x(const T &a) {
        min_f += max(T(0), a - top_R());
        push_R(a);
        push_L(pop_R());
    }

    // add _/
    // f(x) += max(x - a, 0)
    void add_x_minus_a(const T &a) {
        min_f += max(T(0), top_L() - a);
        push_L(a);
        push_R(pop_L());
    }

    // add \/
    // f(x) += abs(x - a)
    void add_abs(const T &a) {
        add_a_minus_x(a);
        add_x_minus_a(a);
    }

//    void add_abs(const T &a) {
//        if (a < top_L()) {
//            min_f += top_L() - a;
//            push_L(a);
//            push_L(a);
//            push_R(pop_L());
//        } else if (top_R() < a) {
//            min_f += a - top_R();
//            push_R(a);
//            push_R(a);
//            push_L(pop_R());
//        } else {
//            push_L(a);
//            push_R(a);
//        }
//    }

    // \/ -> \_
    // f_{new} (x) = min f(y) (y <= x)
    void clear_right() {
        while(R.size() >= 2) R.pop();
    }

    // \/ -> _/
    // f_{new} (x) = min f(y) (y >= x)
    void clear_left() {
        while(L.size() >= 2) L.pop();
    }

    // \/. -> .\/
    // f_{new} (x) = f(x - a)
    void shift(const T &a) {
        add_l += a;
        add_r += a;
    }

    T get(const T &x) {
        T ret = min_f;

        if (!L.empty() && x < top_L()) {
            while(!L.empty()) {
                ret += max(T(0), pop_L() - x);
            }
        }
        if (!R.empty() && top_R() < x) {
            while(!R.empty()) {
                ret += max(T(0), x - pop_R());
            }
        }
        return ret;
    }

};

const int MAXN = 5e5+7;
int a[MAXN], b[MAXN];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i] >> b[i];

    SlopeTrick<LL> trick;
    for (int i = 0; i < n; i++) trick.add_abs(0);

    for (int i = 1; i <= n; i++) {
        trick.shift(-(b[i]-a[i]));
        trick.clear_left();
        trick.add_abs(0);
    }

    cout << trick.get(0) << "\n";

    return 0;
}

• Subtask 1: 24 / 24
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 10 / 10
• Subtask 5: 36 / 36