Submission #772743

#	Time	Username	Problem	Language	Result	Execution time	Memory
772743		BlockOG	Fountain (eJOI20_fountain)	C++14	100 / 100	405 ms	20576 KiB

fountain

#include <iostream>
#include <vector>
#include <utility>
#include <climits>

using namespace std;

int diameters[100000];
int down[100000][20];
int sum[100000][20];

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

    int n, q; cin >> n >> q;

    for (int i = 0; i < n; i++) cin >> diameters[i] >> sum[i][0];

    vector<pair<int, int>> st = { { INT_MAX, -1 } };
    for (int i = n - 1; i >= 0; i--) {
        while (st.back().first <= diameters[i]) st.pop_back();
        down[i][0] = st.back().second;
        st.push_back({ diameters[i], i });
    }

    for (int j = 1; j < 20; j++) {
        for (int i = 0; i < n; i++) {
            if (down[i][j - 1] == -1) {
                down[i][j] = -1;
                sum[i][j] = sum[i][j - 1];
                continue;
            }
            down[i][j] = down[down[i][j - 1]][j - 1];
            sum[i][j] = sum[i][j - 1] + sum[down[i][j - 1]][j - 1];
        }
    }

    for (int it = 0; it < q; it++) {
        int r, v; cin >> r >> v; r--;

        for (int i = 19; i >= 0; i--) {
            if (sum[r][i] >= v) continue;
            v -= sum[r][i];
            r = down[r][i];
            if (r == -1) break;
        }

        cout << r + 1 << endl;
    }
}

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40