Submission #861822

#	Time	Username	Problem	Language	Result	Execution time	Memory
861822		sleepntsheep	Salesman (IOI09_salesman)	C++17	100 / 100	367 ms	37836 KiB

salesman

#include <cstdio>
#include <cstring>
#include <cassert>
#include <string>
#include <deque>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <iostream>
#include <utility>
using namespace std;
using ll =long long;
using ld=long double;

const ll N = 555555, inf = 1e9;
int n, d, u, s, X = 500005;

struct binarytree
{
    int t[N*2];
    binarytree() {memset(t,0xbf,sizeof t);}
    inline int qry(int l, int r)
    {
        int z=-1e9;
        for (l+=X,r+=X+1;l<r;l/=2,r/=2){
            if(l&1)z=max(z,t[l++]);
            if(r&1)z=max(t[--r],z);
        }
        return z;
    }
    inline void upd(int p, int k) { for(t[p+=X]=k;p/=2;)t[p]=max(t[p*2],t[p*2+1]); }
} thi, tlo;

struct fair
{
    int pos, money;
    bool operator<(const fair &o) const { return pos<o.pos; }
};
vector<fair> a[N];

inline void upd(ll pos, ll val)
{
    thi.upd(pos, val - u * pos);
    tlo.upd(pos, val - (X - pos) * d);
}

inline int cost(int pos)
{
    return max(thi.qry(pos, X-1) + u * pos, tlo.qry(0, pos) + (X - pos) * d);
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> u >> d >> s;
    for (int d, p, m, i = 0; i < n; ++i) cin >> d >> p >> m, a[d].push_back(fair{p, m});
    upd(s, 0);
    for (auto i = 0; i <= 500000; ++i)
    {
        auto &x = a[i];
        if (x.empty()) continue;
        sort(x.begin(), x.end());
        if (x.size() == 1)
            upd(x[0].pos, x[0].money + cost(x[0].pos));
        else
        {
            vector<int> temp(x.size(), -inf), rtemp(x.size(), -inf);
            for (int i = 0; i < x.size(); ++i) temp[i] = rtemp[i] = x[i].money + cost(x[i].pos);
            for (int i = 1; i < x.size(); ++i) temp[i] = max(temp[i], temp[i-1] - (x[i].pos - x[i-1].pos) * d + x[i].money);
            for (int i = (int)x.size() - 2; i >= 0; --i) rtemp[i] = max(rtemp[i], rtemp[i+1] - (x[i+1].pos - x[i].pos) * u + x[i].money);
            for (int i = 0; i < x.size(); ++i) upd(x[i].pos, max(temp[i], rtemp[i]));
        }
    }
    cout << cost(s);

    return 0;
}

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:69:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<fair>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |             for (int i = 0; i < x.size(); ++i) temp[i] = rtemp[i] = x[i].money + cost(x[i].pos);
      |                             ~~^~~~~~~~~~
salesman.cpp:70:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<fair>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |             for (int i = 1; i < x.size(); ++i) temp[i] = max(temp[i], temp[i-1] - (x[i].pos - x[i-1].pos) * d + x[i].money);
      |                             ~~^~~~~~~~~~
salesman.cpp:72:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<fair>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |             for (int i = 0; i < x.size(); ++i) upd(x[i].pos, max(temp[i], rtemp[i]));
      |                             ~~^~~~~~~~~~

• Subtask 1: 100 / 100