Submission #570380

#	Time	Username	Problem	Language	Result	Execution time	Memory
570380		grt	Rainforest Jumps (APIO21_jumps)	C++17	33 / 100	4067 ms	5312 KiB

jumps

#include <bits/stdc++.h>
#define PB push_back
#define ST first
#define ND second

//#pragma GCC optimize ("O3")
//#pragma GCC target("tune=native")

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vi = vector<int>;

const int nax = 200 * 1000 + 10, INF = 1e9 + 10;
int n;
int h[nax];
int lft[nax], rght[nax];

void init(int N, vi H) {
	n = N;
	for(int i = 0; i < n; ++i) {
		h[i + 1] = H[i];
	}
	h[0] = INF, h[n + 1] = INF;
	vi S = {0};
	for(int i = 1; i <= n; ++i) {
		while(h[S.back()] < h[i]) S.pop_back();
		lft[i] = S.back();
		S.PB(i);
	}
	S = {n + 1};
	for(int i = n; i >= 1; --i) {
		while(h[S.back()] < h[i]) S.pop_back();
		rght[i] = S.back();
		S.PB(i);
	}
}

int minimum_jumps(int a, int b, int c, int d) {
	a++, b++, c++, d++;
	int res = INF;
	int H = -1;
	for(int i = c; i <= d; ++i) {
		H = max(H, h[i]);
	}
	int p = b;
	for(int i = b - 1; i >= a; --i) {
		if(h[i] > H) break;
		if(h[p] < h[i]) p = i;
	}
	//for(int x = a; x <= b; ++x) {
	int x = p;
		int ans = 0;
		//int xp = x;
		while(x < c) {
			if(h[lft[x]] <= H && h[rght[x]] <= H) {
				if(rght[x] >= c && rght[x] <= d) {
					ans++;
					break;
				}
				if(h[lft[x]] > h[rght[x]]) x = lft[x];
				else x = rght[x];
			} else if(h[lft[x]] <= H) {
				x = lft[x];
			} else if(h[rght[x]] <= H) {
				x = rght[x];
			} else {
				ans = INF;
				break;
			}
			ans++;
		}
		//x = xp;
		res = min(res, ans);
	//}
	return (res == INF ? -1 : res);
}


//int main() {
	//ios_base::sync_with_stdio(0);
	//cin.tie(0);
	//init(7, {3, 2, 1, 6, 4, 5, 7});
	//cout << minimum_jumps(4, 4, 6, 6) << "\n";
	//cout << minimum_jumps(1, 3, 5, 6) << "\n";
	//cout << minimum_jumps(0, 1, 2, 2) << "\n";
//}

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