Submission #603682

#	Time	Username	Problem	Language	Result	Execution time	Memory
603682		KoD	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1307 ms	47896 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>

using ll = long long;
using std::array;
using std::vector;
using std::pair;

constexpr int LOG = 18;

class range_max {
    int size;
    vector<int> data;

  public:
    range_max() = default;

    explicit range_max(const vector<int>& v) {
        size = (int)v.size();
        data.resize(2 * size);
        for (int i = 0; i < size; ++i) {
            data[size + i] = v[i];
        }
        for (int i = size - 1; i > 0; --i) {
            data[i] = std::max(data[2 * i], data[2 * i + 1]);
        }
    }

    int fold(int l, int r) const {
        l += size, r += size;
        int ret = 0;
        while (l < r) {
            if (l & 1) ret = std::max(ret, data[l++]);
            if (r & 1) ret = std::max(ret, data[--r]);
            l >>= 1;
            r >>= 1;
        }
        return ret;
    }
};

vector<int> height;
range_max rmq;
array<vector<int>, LOG> left, right, high;

void init(int N, vector<int> H) {
    height.reserve(N + 2);
    height.push_back(N + 1);
    for (const int x : H) {
        height.push_back(x);
    }
    height.push_back(N + 1);
    rmq = range_max(height);
    N += 2;
    for (int k = 0; k < LOG; ++k) {
        left[k].resize(N);
        right[k].resize(N);
        high[k].resize(N);
    }
    vector<int> stack;
    for (int i = 0; i < N; ++i) {
        while (!stack.empty() and height[i] > height[stack.back()]) {
            stack.pop_back();
        }
        left[0][i] = stack.empty() ? i : stack.back();
        stack.push_back(i);
    }
    for (int i = N - 1; i >= 0; --i) {
        while (!stack.empty() and height[i] > height[stack.back()]) {
            stack.pop_back();
        }
        right[0][i] = stack.empty() ? i : stack.back();
        stack.push_back(i);
    }
    for (int i = 0; i < N; ++i) {
        high[0][i] = height[left[0][i]] > height[right[0][i]] ? left[0][i] : right[0][i];
    }
    for (int k = 0; k + 1 < LOG; ++k) {
        for (int i = 0; i < N; ++i) {
            left[k + 1][i] = left[k][left[k][i]];
            right[k + 1][i] = right[k][right[k][i]];
            high[k + 1][i] = high[k][high[k][i]];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    A += 1, B += 1, C += 1, D += 1;
    const int goal_max = rmq.fold(C, D + 1);
    if (rmq.fold(B, C) > goal_max) {
        return -1;
    }
    int ans = 0, u = B;
    for (int k = LOG - 1; k >= 0; --k) {
        if (height[left[k][u]] < goal_max and left[k][u] >= A) {
            u = left[k][u];
        }
    }
    if (right[0][u] >= C) {
        return ans + 1;
    }
    for (int k = LOG - 1; k >= 0; --k) {
        if (right[0][high[k][u]] < C) {
            ans += 1 << k;
            u = high[k][u];
        }
    }
    if (height[left[0][u]] > goal_max) {
        for (int k = LOG - 1; k >= 0; --k) {
            if (right[k][u] < C) {
                ans += 1 << k;
                u = right[k][u];
            }
        }
        return ans + 1;
    } else {
        return ans + 2;
    }
}

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