Submission #1299502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299502		SabaKharebava	Obstacles for a Llama (IOI25_obstacles)	C++20	0 / 100	2097 ms	11308 KiB

obstacles

#include<bits/stdc++.h>

using namespace std;

const int mxN = 200000;

#define pb push_back

class seg_tree {
private:
	int n;
	vector<int> tree;

	void build(int u, int l, int r, vector<int> &v) {
		if (l > r || r < 0 || l >= n)
			return;
		if (l == r) {
			tree[u] = v[l];
			return;
		}

		int mid = (l+r)/2;
		build(2*u, l, mid, v);
		build(2*u + 1, mid+1, r, v);

		tree[u] = min(tree[2*u], tree[2*u + 1]);
	}

	int query(int u, int l, int r, int ql, int qr) {
		if (l > r || r < 0 || l >= n)
			return INT_MAX;
		if (ql <= l && qr >= r)
			return tree[u];
		if (l == r)
			return INT_MAX;

		int mid = (l+r)/2;
		return min(query(2*u, l, mid, ql, qr), query(2*u + 1, mid+1, r, ql, qr));
	}

public:
	void build(vector<int> &v) {
		n = v.size();
		tree.resize(4*n);
		build(1, 0, n, v);
	}

	int query(int l, int r) {
		return query(1, 0, n, l, r);
	}
};

vector<pair<int, int>> reach;
vector<int> inc = {0}, mx, lvl, t;
seg_tree tree;

void initialize(vector<int> T, vector<int> H) {
	t = T;
	tree.build(H);
	reach.resize(H.size());
	lvl.resize(H.size());
	mx.pb(T[0]);
	for (int i = 1; i < T.size(); i++) {
		if (T[inc.back()] < T[i])
			inc.pb(i);
		mx.pb(min(mx.back(), T[i]));
	}
	/*
	cout<< "INC :\n\t";
	for (int e : inc)
		cout<< e << ' ';
	cout<< '\n';
	*/
	for (int i = 0; i < H.size(); i++) {
		if (H[i] >= T[0]) {
			reach[i].first = -1;
			reach[i].second = -1;
			continue;
		}
		
		int j = i;
		while (j+1 < H.size() && H[j+1] < T[0])
			j++;

		int seg_l = i, seg_r = j;
		int l = 0, r = inc.size(), mid, mn = tree.query(seg_l, seg_r);
		int lv;
		//cout<< seg_l << " -> " << seg_r << " :\n";
		while (l < r) {
			mid = (l+r)/2;
			//cout<< '\t' << l << ' ' << mid << ' ' << r << '\n';
			if (mx[inc[mid]] <= mn)
				r = mid;
			else {
				lv = mid;
				l = mid+1;
			}
		}
		//cout<< "\tRESULT : " << lv << '\n';

		while (seg_l-1 >= 0 && T[inc[lv]] > H[seg_l-1])
			seg_l--;
		while (seg_r+1 < H.size() && T[inc[lv]] > H[seg_r+1])
			seg_r++;

		for (int ind = i; ind <= j; ind++) {
			lvl[ind] = inc[lv];
			reach[ind].first = seg_l;
			reach[ind].second = seg_r;
		}
		i = j;
	}
	/*
	cout<< "REACH :\n";
	for (int i = 0; i < H.size(); i++) {
		cout<< '\t' << i << " -> (" << reach[i].first << "; " << reach[i].second << ")\n";
	}
	*/
}

bool can_reach(int L, int R, int S, int D) {
	int lv = max(lvl[S], lvl[D]);
	int l = max(reach[S].first, reach[D].first);
	int r = min(reach[S].second, reach[D].second);
	
	if (l > r)
		return false;
	int mn = tree.query(l, r);
	return (mn < t[lv]);
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 13
• Subtask 4: 0 / 21
• Subtask 5: 0 / 25
• Subtask 6: 0 / 17