Submission #648439

#	Time	Username	Problem	Language	Result	Execution time	Memory
648439		Alexandruabcde	Rainforest Jumps (APIO21_jumps)	C++14	4 / 100	1591 ms	44988 KiB

jumps

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

using namespace std;

constexpr int LOGMAX = 20;
constexpr int NMAX = 2e5 + 5;

int st[LOGMAX][NMAX];
int dr[LOGMAX][NMAX];
int bst[LOGMAX][NMAX];
int Lg[NMAX];

int vf;

void init(int N, std::vector<int> H) {
    deque <int> D;
    Lg[1] = 0;
    for (int i = 2; i <= N; ++ i )
        Lg[i] = Lg[i/2] + 1;

    vf = Lg[N];

    for (int i = 0; i <= vf; ++ i )
        for (int j = 0; j < N; ++ j )
            st[i][j] = dr[i][j] = bst[i][j] = -1;

    for (int i = 0; i < N; ++ i ) {
        while (!D.empty() && H[D.back()] < H[i]) {
            dr[0][D.back()] = i;

            D.pop_back();
        }

        if (!D.empty()) st[0][i] = D.back();

        D.push_back(i);
    }

    for (int i = 0; i < N; ++ i ) {
        bst[0][i] = -1;

        if (st[0][i] == -1) bst[0][i] = dr[0][i];
        else if (dr[0][i] == -1) bst[0][i] = st[0][i];
        else {
            bst[0][i] = (H[st[0][i]] > H[dr[0][i]] ? st[0][i] : dr[0][i]);
        }
    }

    for (int i = 1; i <= Lg[N]; ++ i ) {
        for (int j = 0; j + (1<<i) - 1 < N; ++ j ) {
            if (st[i-1][j] == -1) st[i][j] = -1;
            else st[i][j] = st[i-1][st[i-1][j]];

            if (dr[i-1][j] == -1) dr[i][j] = -1;
            else dr[i][j] = dr[i-1][dr[i-1][j]];

            if (bst[i-1][j] == -1) bst[i][j] = -1;
            else bst[i][j] = bst[i-1][bst[i-1][j]];
        }
    }
}

int Can (int pos, int C, int D) {
    int ans = 0;
    if (C <= pos && pos <= D) return 0;

    for (int i = vf; i >= 0; -- i ) {
        if (dr[i][pos] == -1) continue;

        if (dr[i][pos] >= C) continue;

        pos = dr[i][pos];
        ans += (1<<i);
    }

    pos = dr[0][pos];
    ++ ans;

    return (pos <= D ? ans : -1);
}

int minimum_jumps(int A, int B, int C, int D) {
    int best_pos_AB = B;

    if (Can(B, C, D) == -1) return -1;

    for (int i = vf; i >= 0; -- i ) {
        if (st[i][best_pos_AB] == -1) continue;

        if (st[i][best_pos_AB] < A) continue;

        int new_pos = st[i][best_pos_AB];
        if (Can(new_pos, C, D) >= 0) best_pos_AB = new_pos;
    }

    int answer = Can(best_pos_AB, C, D);
    int contor = 0;

    for (int i = vf; i >= 0; -- i ) {
        if (bst[i][best_pos_AB] == -1) continue;

        if (bst[i][best_pos_AB] >= C) continue;

        int new_pos = bst[i][best_pos_AB];
        int x;

        if ((x = Can(new_pos, C, D)) >= 0) {
            contor += (1<<i);
            answer = x + contor;
            best_pos_AB = bst[i][best_pos_AB];
        }
    }

    return answer;
}

• Subtask 1: 4 / 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