Submission #971431

#	Time	Username	Problem	Language	Result	Execution time	Memory
971431		Pannda	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	4043 ms	71784 KiB

jumps

#include "jumps.h"

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

struct SegmentTree {
    struct Node {
        int sum = 0;
        int ln = 0, rn = 0;
    };

    int n;
    vector<Node> nodes;
    vector<int> roots;

    SegmentTree() {}
    SegmentTree(int n) : n(n), nodes(1), roots(1, 0) {}

    void add(int i, int delta, int base, int &idx, int l, int r) {
        idx = nodes.size();
        nodes.push_back(nodes[base]);
        nodes[idx].sum += delta;
        if (l + 1 < r) {
            int m = (l + r) >> 1;
            Node goat = nodes[idx];
            if (i < m) add(i, delta, nodes[base].ln, goat.ln, l, m);
            else add(i, delta, nodes[base].rn, goat.rn, m, r);
            nodes[idx] = goat;
        }
    }

    void add(int i, int val) {
        roots.emplace_back();
        add(i, val, roots.end()[-2], roots.end()[-1], 0, n);
    }

    int find(int ub, int idxl, int idxr) {
        auto dfs = [&](auto self, int idxl, int idxr, int l, int r) -> int {
            if (l >= ub) return -1;
            if (nodes[idxr].sum - nodes[idxl].sum == 0) return -1;
            if (l + 1 == r) return l;
            int m = (l + r) >> 1;
            int get = self(self, nodes[idxl].rn, nodes[idxr].rn, m, r);
            if (get != -1) return get;
            return self(self, nodes[idxl].ln, nodes[idxr].ln, l, m);
        };
        return dfs(dfs, idxl, idxr, 0, n);
    }
};

const int LOG = 17;
int n;
vector<int> h, ih;
vector<vector<int>> f;
vector<int> depth;
SegmentTree seg;

void init(int N, vector<int> H) {
    n = N;
    h = H;
    ih = vector<int>(n);
    for (int i = 0; i < n; i++) {
        h[i]--;
        ih[h[i]] = i;
    }
    h.push_back(n);
    f = vector<vector<int>>(n + 1, vector<int>(LOG, n));
    depth = vector<int>(n + 1, 0);

    vector<int> stk = { n };
    for (int i = n - 1; i >= 0; i--) {
        while (h[stk.back()] < h[i]) stk.pop_back();
        depth[i] = depth[stk.back()] + 1;
        f[i][0] = stk.back();
        stk.push_back(i);
    }

    stk.clear();
    for (int i = 0; i < n; i++) {
        while (!stk.empty() && h[stk.back()] < h[i]) stk.pop_back();
        if (!stk.empty() && depth[stk.back()] <= depth[f[i][0]]) {
            f[i][0] = stk.back();
        }
        stk.push_back(i);
    }

    for (int k = 1; k < LOG; k++) {
        for (int i = 0; i < n; i++) {
            f[i][k] = f[f[i][k - 1]][k - 1];
        }
    }

    seg = SegmentTree(n + 1);
    for (int i = 0; i < n; i++) {
        seg.add(h[i], +1);
    }
}

int minimum_jumps(int l0, int r0, int l1, int r1) {
    r0++; r1++;

    int res = n;

    for (int to = l1; to < r1; to++) {
        int from = seg.find(h[to], seg.roots[l0], seg.roots[r0]);
        if (from == -1) continue;
        from = ih[from];
        int cnt = 0;
        for (int k = LOG - 1; k >= 0; k--) {
            int next = f[from][k];
            if (depth[next] >= depth[to]) {
                from = next;
                cnt += 1 << k;
            }
        }
        res = min(res, cnt + depth[from] - depth[to]);
    }

    if (res == n) return -1;
    return res;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 0 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19