Submission #1100073

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100073		fve5	Nile (IOI24_nile)	C++17	38 / 100	90 ms	13764 KiB

nile

#pragma GCC optimize("trapv")
#include "nile.h"
#include <bits/stdc++.h>
using namespace std;

typedef long long i64;

struct CC {
    static vector<int> A, B;
    static vector<i64> S;

    int par, size, l, r, best;

    void skip(int i) { best = min(best, A[i] - B[i]); }

    i64 get_best() const { return min({best, A[l] - B[l], A[r] - B[r]}); }
    i64 get_cost() const { return S[r + 1] - S[l] + (size & 1) * get_best(); }
};
vector<int> CC::A = {};
vector<int> CC::B = {};
vector<i64> CC::S = {};

struct DSU {
    vector<CC> arr;
    i64 cost;

    int find(int u) {
        if (arr[u].par == u) return u;
        return arr[u].par = find(arr[u].par);
    }

    void join(int i) {
        int u = find(i);
        int v = find(i + 1);
        
        if (u == v) return;
        if (arr[u].size < arr[v].size) swap(u, v);

        cost -= arr[u].get_cost();
        cost -= arr[v].get_cost();

        arr[u].size += arr[v].size;
        arr[u].r = max(arr[u].r, arr[v].r);
        arr[u].l = min(arr[u].l, arr[v].l);
        arr[u].best = max(arr[u].best, arr[v].best);

        arr[v].par = u;

        cost += arr[u].get_cost();
    }

    void skip(int i) {
        int u = find(i);

        cost -= arr[u].get_cost();
        arr[u].skip(i);
        cost += arr[u].get_cost();
    }

    DSU(int N) : arr(N), cost(0) {
        for (int i = 0; i < N; i++) {
            arr[i] = {i, 1, i, i, (int)2e9};
            cost += arr[i].get_cost();
        }
    }
};

enum EventType { JOIN, SKIP, QUERY };
struct Event {
    EventType type;
    int time, position;
};

bool operator<(const Event &a, const Event &b) { return tie(a.time, a.type) < tie(b.time, b.type); }

vector<long long> calculate_costs(vector<int> W, vector<int> A, vector<int> B, vector<int> E) {
    vector<int> order(W.size());
    iota(order.begin(), order.end(), 0);
    sort(order.begin(), order.end(), [&](int u, int v) { return W[u] < W[v]; });
    sort(W.begin(), W.end());

    CC::A.resize(W.size());
    CC::B.resize(W.size());
    CC::S.resize(W.size() + 1);

    for (int i = 0; i < W.size(); i++) {
        CC::A[i] = A[order[i]];
        CC::B[i] = B[order[i]];
        CC::S[i + 1] = CC::S[i] + B[order[i]];
    }

    vector<Event> events;
    for (int i = 0; i < E.size(); i++)
        events.push_back({QUERY, E[i], i});
    for (int i = 0; i < W.size() - 1; i++)
        events.push_back({JOIN, W[i + 1] - W[i], i});
    for (int i = 1; i < W.size() - 1; i++)
        events.push_back({SKIP, W[i + 1] - W[i - 1], i});
    
    DSU dsu(W.size());
    vector<i64> ans(E.size());
    sort(events.begin(), events.end());

    for (auto [type, _, idx]: events) {
        switch (type) {
        case JOIN:
            dsu.join(idx);
            break;
        case SKIP:
            dsu.skip(idx);
            break;
        case QUERY:
            ans[idx] = dsu.cost;
            break;
        }
    }

    return ans;
}

Compilation message (stderr)

nile.cpp: In function 'std::vector<long long int> calculate_costs(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
nile.cpp:86:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |     for (int i = 0; i < W.size(); i++) {
      |                     ~~^~~~~~~~~~
nile.cpp:93:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |     for (int i = 0; i < E.size(); i++)
      |                     ~~^~~~~~~~~~
nile.cpp:95:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |     for (int i = 0; i < W.size() - 1; i++)
      |                     ~~^~~~~~~~~~~~~~
nile.cpp:97:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |     for (int i = 1; i < W.size() - 1; i++)
      |                     ~~^~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 6 / 6
• Subtask 2: 0 / 13
• Subtask 3: 17 / 17
• Subtask 4: 0 / 11
• Subtask 5: 0 / 20
• Subtask 6: 15 / 15
• Subtask 7: 0 / 18