Submission #611808

#	Time	Username	Problem	Language	Result	Execution time	Memory
611808		Jomnoi	Meetings (IOI18_meetings)	C++17	0 / 100	2512 ms	21936 KiB

meetings

#include <bits/stdc++.h>
#include "meetings.h"
using namespace std;

const int MAX_N = 75e4 + 5;

int N, Q;
long long H[MAX_N];
pair <int, int> table[MAX_N][20];
vector <int> graph[MAX_N];

pair <int, int> getMax(int l, int r) {
    int j = log2(r - l + 1);
    return max(table[l][j], table[r - (1<<j) + 1][j]);
}

int build_tree(int l, int r) {
    if(l > r) {
        return -1;
    }

    int u = getMax(l, r).second;
    int L = build_tree(l, u - 1);
    int R = build_tree(u + 1, r);
    if(L != -1) {
        graph[u].push_back(L);
    }
    if(R != -1) {
        graph[u].push_back(R);
    }
    return u;
}

long long dfs(int u, int l, int r, long long total = 0) {
    long long now = H[u] * (r - l + 1) + total;
    for(auto v : graph[u]) {
        if(v < u) {
            now = min(now, dfs(v, l, u - 1, total + H[u] * (r - u + 1)));
        }
        else {
            now = min(now, dfs(v, u + 1, r, total + H[u] * (u - l + 1)));
        }
    }
    return now;
}

vector <long long> minimum_costs(vector <int> h, vector <int> L, vector <int> R) {
    N = h.size(), Q = L.size();

    for(int i = 1; i <= N; i++) {
        H[i] = h[i - 1];

        table[i][0] = make_pair(H[i], i);
    }
    for(int j = 1; j < 20; j++) {
        for(int i = 1; i + (1<<j) - 1 <= N; i++) {
            table[i][j] = max(table[i][j - 1], table[i + (1<<(j - 1))][j - 1]);
        }
    }

    int root = build_tree(1, N);

    vector <long long> C;
    for(int i = 0; i < Q; i++) {
        L[i]++, R[i]++;
        int rt = getMax(L[i], R[i]).second;
        C.push_back(dfs(rt, L[i], R[i]));
    }
    return C;
}

Compilation message (stderr)

meetings.cpp: In function 'std::vector<long long int> minimum_costs(std::vector<int>, std::vector<int>, std::vector<int>)':
meetings.cpp:61:9: warning: unused variable 'root' [-Wunused-variable]
   61 |     int root = build_tree(1, N);
      |         ^~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 15
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 40