Submission #1074034

#	Time	Username	Problem	Language	Result	Execution time	Memory
1074034		Gromp15	Radio Towers (IOI22_towers)	C++17	11 / 100	4075 ms	180176 KiB

towers

#include <bits/stdc++.h>
#include "towers.h"
#define ll long long
#define ar array
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
using namespace std;

template<typename T> bool ckmin(T &a, const T &b ) { return a > b ? a = b, 1 : 0; }
template<typename T> bool ckmax(T &a, const T &b ) { return a < b ? a = b, 1 : 0; }

int N; vector<int> h;
void init(int _N, std::vector<int> H) {
	N = _N;
	h = H;
}

struct seg {
	int N; vector<ar<int, 2>> tree;
	seg(int n, const vector<int>& h) : N(1<<(__lg(n)+1)), tree(2*N) {
		for (int i = 0; i < n; i++) tree[i+N] = {h[i], i};
		for (int i = N-1; i >= 1; i--) tree[i] = max(tree[i*2], tree[i*2+1]);
	}
	ar<int, 2> query(int node, int nl, int nr, int ql, int qr) {
		if (ql > nr || qr < nl) return {};
		if (ql <= nl && nr <= qr) return tree[node];
		int mid = (nl+nr)/2;
		return max(query(node*2, nl, mid, ql, qr), query(node*2+1, mid+1, nr, ql, qr));
	}
};



int max_towers(int L, int R, int D) {
	seg st(N, h);
	map<ar<int, 3>, int> mp;
	auto solve = [&](auto&& s, int l, int r, int lim) -> int {
		if (mp.count({l, r, lim})) return mp[{l, r, lim}];
		if (l > r) return 0;
		if (l == r) return h[l] <= lim;
		int p = st.query(1, 0, st.N-1, l, r)[1];
		return mp[{l, r, lim}] = max({s(s, l, p-1, lim), s(s, p+1, r, lim), int(h[p] <= lim), s(s, l, p-1, h[p] - D) + s(s, p+1, r, h[p] - D)});
	};
	solve(solve, L, R, 1e9);
	return solve(solve, L, R, 1e9);
}

• Subtask 1: 0 / 4
• Subtask 2: 11 / 11
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23