Submission #556970

#	Time	Username	Problem	Language	Result	Execution time	Memory
556970		timreizin	Salesman (IOI09_salesman)	C++17	50 / 100	3068 ms	65536 KiB

salesman

#include <iostream>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <string>
#include <numeric>
#include <cmath>
#include <cassert>
#include <array>
#include <numeric>

using namespace std;

using ll = long long;

class SegmentTree
{
private:
    
    int amount;
    vector<ll> tree;
    
    ll get(int a, int b, int l, int r, int v)
    {
        if (a > r || b < l) return -1e9;
        if (a == l && b == r) return tree[v];
        int m = (l + r) >> 1;
        return max(get(a, min(b, m), l, m, v << 1), get(max(a, m + 1), b, m + 1, r, (v << 1) + 1));
    }
    
    void build(int l, int r, int v)
    {
        if (l > r) return;
        if (l == r)
        {
            tree[v] = -1e9;
            return;
        }
        int m = (l + r) >> 1;
        build(l, m, v << 1);
        build(m + 1, r, (v << 1) + 1);
        tree[v] = max(tree[v << 1], tree[(v << 1) + 1]);
    }
    
    void update(int p, int l, int r, int v, ll value)
    {
        if (l > r) return;
        if (l == r)
        {
            tree[v] = value;
            return;
        }
        int m = (l + r) >> 1;
        if (p <= m) update(p, l, m, v << 1, value);
        else update(p, m + 1, r, (v << 1) + 1, value);
        tree[v] = max(tree[v << 1], tree[(v << 1) + 1]);
    }
    
public:
    
    SegmentTree(int n = 0) : amount(n)
    {
        tree.resize(4 * amount + 5);
        build(0, n - 1, 1);
    }
    
    ll get(int a, int b)
    {
        return get(a, b, 0, amount - 1, 1);
    }
    
    void update(int p, ll value)
    {
        update(p, 0, amount - 1, 1, value);
    }
};

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    int n;
    ll d, u, s;
    cin >> n >> u >> d >> s;
    vector<tuple<int, ll, ll>> fairs(n);
    for (auto &[t, l, m] : fairs) cin >> t >> l >> m;
    sort(fairs.begin(), fairs.end());
    vector<vector<pair<ll, ll>>> times;
    int last = get<0>(fairs.front());
    times.push_back(vector<pair<ll, ll>>());
    for (auto [t, l, m] : fairs)
    {
        if (t != last) times.push_back(vector<pair<ll, ll>>());
        times.back().emplace_back(l, m);
        last = t;
    }
    ll res = 0;
    SegmentTree left(500002), right(500002);
    left.update(s, s * d);
    right.update(s, -s * u);
    for (auto &fairs : times)
    {
        vector<ll> dp(fairs.size(), -1e9);
        for (int i = 0; i < dp.size(); ++i)
        {
            ll sum = 0;
            for (int j = i; j >= 0; --j)
            {
                sum += fairs[j].second;
                ll bestj = max(left.get(0, fairs[j].first) - d * fairs[j].first, right.get(fairs[j].first, 500001) + u * fairs[j].first);
                dp[i] = max(dp[i], bestj + sum);
            }
        }
        for (int i = (int)dp.size() - 1; i >= 0; --i)
        {
            ll sum = 0;
            for (int j = i; j < dp.size(); ++j)
            {
                sum += fairs[j].second;
                ll bestj = max(left.get(0, fairs[j].first) - d * fairs[j].first, right.get(fairs[j].first, 500001) + u * fairs[j].first);
                dp[i] = max(dp[i], bestj + sum);
            }
        }
        for (int i = 0; i < dp.size(); ++i)
        {
            ll move = (s < fairs[i].first ? u * (fairs[i].first - s) : d * (s - fairs[i].first));
            res = max(res, dp[i] - move);
            left.update(fairs[i].first, dp[i] + fairs[i].first * d);
            right.update(fairs[i].first, dp[i] - fairs[i].first * u);
        }
    }
    cout << res;
    return 0;
}
/*
4 5 3 100
2 80 100
20 125 130
10 75 150
5 120 110
*/

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:104:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  104 |         for (int i = 0; i < dp.size(); ++i)
      |                         ~~^~~~~~~~~~~
salesman.cpp:117:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |             for (int j = i; j < dp.size(); ++j)
      |                             ~~^~~~~~~~~~~
salesman.cpp:124:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  124 |         for (int i = 0; i < dp.size(); ++i)
      |                         ~~^~~~~~~~~~~

• Subtask 1: 50 / 100