Submission #984289

#	Time	Username	Problem	Language	Result	Execution time	Memory
984289		Marcus	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	4033 ms	41916 KiB

jumps

#include "jumps.h"
#include <vector>

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

int n;
vector<int> h;
const int INF = 2e6;
vector<vector<int>> adj(2e5);
int k;
vector<vector<int>> st1;
vector<vector<int>> st2;
 
void init(int N, std::vector<int> H) {
    n = N;
    for (auto u: H) {h.push_back(u);}
    h.shrink_to_fit();

    for (int i=0; i<n; i++)
    {
        for (int j=i; j<n; j++)
        {
            if (h[i] < h[j]) {adj[i].push_back(j); break;};
        }
        for (int j=i; j>=0; j--)
        {
            if (h[i] < h[j]) {adj[i].push_back(j); break;};
        }
    }

    k = (int)__lg(n);
    st1.resize(k+1); for (auto &u: st1) {u.resize(n, -1);}
    st2.resize(k+1); for (auto &u: st2) {u.resize(n, -1);} 

    for (int j = 0; j < n; j++)
    {
        if (adj[j].size() == 2)
        {
            int x = adj[j][0]; int y = adj[j][1];
            if (h[x] > h[y]) {st1[0][j] = x; st2[0][j] = y;}
            else {st1[0][j] = y; st2[0][j] = x;}
        }
        else if (adj[j].size() == 1)
        {
            int x = adj[j][0];
            st2[0][j] = x;
        }
    }

    for (int i = 1; i <= k; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (st1[i-1][j] != -1) st1[i][j] = st1[i-1][st1[i-1][j]];
            if (st2[i-1][j] != -1) st2[i][j] = st2[i-1][st2[i-1][j]];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    int answer = 0;
    int point = A;
    for (int i = k; i >= 0; i--) {
        if (st1[i][point] != -1 && h[st1[i][point]] <= h[C]) {
            answer += (int)pow(2, i);
            point = st1[i][point];
        }
        if (point == C) return answer;
    }
    for (int i = k; i >= 0; i--) {
        if (st2[i][point] != -1 && h[st2[i][point]] <= h[C]) {
            answer += (int)pow(2, i);
            point = st2[i][point];
        }
        if (point == C) return answer;
    }
    return -1;
}

• 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