Submission #744943

#	Time	Username	Problem	Language	Result	Execution time	Memory
744943		RushB	Rainforest Jumps (APIO21_jumps)	C++17	23 / 100	1048 ms	39892 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;
const int L = 20;
int prv[N], nxt[N], n, h[N], sparse[N][L];
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);
	}
	for (int i = n - 1; i >= 0; i--) h[i] = h[nxt[i]] + 1;
	
	for (int i = 0; i < n; i++) {
		int x = (prv[i] == -1 ? -1 : H[prv[i]]), y = (nxt[i] == n ? -1 : H[nxt[i]]);
		if (y == -1 && x == -1) sparse[i][0] = i;
		else sparse[i][0] = (x > y ? prv[i] : nxt[i]);
	}
		
	FOR(j, 1, L) FOR(i, 0, n) sparse[i][j] = sparse[sparse[i][j - 1]][j - 1];

}

int minimum_jumps(int A, int B, int C, int D) {
	assert(A == B && C == D);
	if (prv[C] >= A) return -1;
	int t = 0;
	for (int i = L - 1; i >= 0; i--) if (H[sparse[A][i]] < H[C]) {
		A = sparse[A][i];
		t |= 1 << i;
	}
	return t + h[A] - h[C];
}

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