Submission #637612

#	Time	Username	Problem	Language	Result	Execution time	Memory
637612		stoyan_malinin	Long Distance Coach (JOI17_coach)	C++14	100 / 100	145 ms	25076 KiB

coach

#include <algorithm>
#include <iostream>
#include <vector>
#include <cmath>
#include <set>

using namespace std;

const int MAXN = 2e5;
const int64_t inf = 1e18;
const int64_t MAXX = 1e12;

struct Line
{
    int64_t a, b;

    Line(){}
    Line(double a, double b)
    {
        this->a = a;
        this->b = b;
    }

    int64_t get(int64_t x)
    {
        return a*x + b;
    }
};

double intersect(const Line &A, const Line &B)
{
    return double(B.b-A.b)/double(A.a-B.a);
}

struct ConvexHullTrick
{
    vector <Line> v;
    vector <double> to;

    void add(const Line &l)
    {
        while(v.size()>=2 && to.back()>=intersect(v[v.size()-2], l))
        {
            v.pop_back();
            to.pop_back();
        }

        if(v.empty()==true)
        {
            v.push_back(l);
        }
        else
        {
            to.push_back(intersect(v.back(), l));
            v.push_back(l);
        }
    }

    int64_t get(double x)
    {
        auto it = upper_bound(to.begin(), to.end(), x);
        return v[it-to.begin()].get(x);
    }
};

struct Passanger
{
    int64_t d, c;

    Passanger(){}
    Passanger(int64_t d, int64_t c) : d(d), c(c) {}
};

int64_t X, n, m, W, T;
int64_t sources[MAXN+5];
Passanger passangers[MAXN+5];
Passanger passangersPref[MAXN+5];

int64_t depart[MAXN+5];
int64_t endWaterPoints[MAXN+5];
int64_t endWaterPointsPrefix[MAXN+5];

int findLastPassangerBefore(int64_t rem)
{
    int l = 0, r = m - 1, mid;
    while(l+1<r)
    {
        mid = (l+r)/2;

        if(passangers[mid].d<rem) l = mid;
        else r = mid - 1;
    }

    if(passangers[r].d<rem) return r;
    if(passangers[l].d<rem) return l;
    return -1;
}

void init()
{
    sort(sources, sources+n);
    sort(passangers, passangers+m,
    [](const Passanger& A, const Passanger& B)
    {
        if(A.d!=B.d) return A.d<B.d;
        return A.c<B.c;
    });

    for(int i = 0;i<m;i++) depart[i] = -1;

    for(int i = 0;i<n;i++)
    {
        int ind = findLastPassangerBefore(sources[i]%T);
        if(ind!=-1 && depart[ind]==-1) depart[ind] = sources[i];
    }
    {
        int ind = findLastPassangerBefore(X%T);
        if(ind!=-1 && depart[ind]==-1) depart[ind] = X;
    }
}

int64_t dp[MAXN+5];

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

    cin >> X >> n >> m >> W >> T;
    for(int i = 0;i<n;i++) cin >> sources[i];
    for(int i = 0;i<m;i++) cin >> passangers[i].d >> passangers[i].c;
    init();

    int64_t driverWater = X/T + 1;

    int64_t endWaterPointsSum = 0;
    for(int i = 0;i<m;i++)
    {
        endWaterPoints[i] = ((X-passangers[i].d+(T-1))/T)*T + passangers[i].d;
        endWaterPointsSum += endWaterPoints[i];

        endWaterPointsPrefix[i] = endWaterPoints[i];
        if(i!=0) endWaterPointsPrefix[i] += endWaterPointsPrefix[i-1];
    }

    int64_t beginWaterPointsSum = 0;
    for(int i = 0;i<m;i++) beginWaterPointsSum += passangers[i].d;

    passangersPref[0] = passangers[0];
    for(int i = 1;i<m;i++)
    {
        passangersPref[i].d = passangersPref[i-1].d + passangers[i].d;
        passangersPref[i].c = passangersPref[i-1].c + passangers[i].c;
    }

    ConvexHullTrick cht;

    for(int i = 0;i<m;i++)
    {
        dp[i] = inf;
        if(i!=0) dp[i] = dp[i-1];
        else dp[i] = 0;

        {
                int64_t lastDp = ((i==0)?0:dp[i-1]);
                int64_t lastEWPP = ((i==0)?0:endWaterPointsPrefix[i-1]);
                int64_t lastC = ((i==0)?0:passangersPref[i-1].c);
                int64_t lastD = ((i==0)?0:passangersPref[i-1].d);

                cht.add(Line(W*(-i), lastDp - lastC + ((-lastD + lastEWPP)/T)*W));
        }

        if(depart[i]!=-1)
        {
            int64_t based = (depart[i]/T)*T;
            int64_t basedDiv = depart[i]/T;
            int64_t val1 = ((passangersPref[i].d - endWaterPointsPrefix[i])/T)*W + basedDiv*(i+1)*W + passangersPref[i].c;
            int64_t val2 = cht.get(basedDiv);

            dp[i] = min(dp[i], val1 + val2);
        }
    }

    int64_t ans = dp[m-1] + ((endWaterPointsSum-beginWaterPointsSum)/T)*W + driverWater*W;
    cout << ans << '\n';
}
/*
19 1 4 8 7
10
1 20
2 10
4 5
6 5
*/

Compilation message (stderr)

coach.cpp: In function 'int main()':
coach.cpp:175:21: warning: unused variable 'based' [-Wunused-variable]
  175 |             int64_t based = (depart[i]/T)*T;
      |                     ^~~~~

• Subtask 1: 16 / 16
• Subtask 2: 30 / 30
• Subtask 3: 25 / 25
• Subtask 4: 29 / 29