Submission #744932

#	Time	Username	Problem	Language	Result	Execution time	Memory
744932		RushB	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	4016 ms	5664 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i < (b); i++) 
using namespace std;
const int N = 2e5 + 5;
int prv[N], nxt[N], n;
vector<int> H;

void init(int _n, std::vector<int> _H) {
	n = _n;
	H.swap(_H);	

	vector<int> st;
	FOR(i, 0, n) {
		while (st.size() && H[st.back()] <= H[i]) st.pop_back();
		prv[i] = (st.empty() ? -1 : st.back());
		st.push_back(i);
	}
	st.clear();
	for (int i = n - 1; i >= 0; i--) {
		while (st.size() && H[st.back()] <= H[i]) st.pop_back();
		nxt[i] = (st.empty() ? n : st.back());
		st.push_back(i);
	}
}

int minimum_jumps(int A, int B, int C, int D) {
	assert(A == B && C == D);
	int t = 0;
	while (A != C) {
		int x = (prv[A] == -1 || H[prv[A]] > H[C] ? -1 : H[prv[A]]), y = (nxt[A] == n || H[nxt[A]] > H[C] ? -1 : H[nxt[A]]);
		if (x == y && x == -1) return -1;
		A = (x > y ? prv[A] : nxt[A]);
		t++;
	}
	return t;
}

• 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