Submission #422760

#	Time	Username	Problem	Language	Result	Execution time	Memory
422760		KoD	Sky Walking (IOI19_walk)	C++17	15 / 100	294 ms	26276 KiB

walk

#include <bits/stdc++.h>
#include "walk.h"

using ll = long long;
template <class T> using Vec = std::vector<T>;

constexpr ll INF = std::numeric_limits<ll>::max() / 2;

ll min_distance(Vec<int> x, Vec<int> h, Vec<int> l, Vec<int> r, Vec<int> y, int s, int g) {
	const int n = (int) x.size();
	const int m = (int) y.size();
	if (s == 0 and g == n - 1) {
		Vec<Vec<int>> start(n), end(n);
		for (int i = 0; i < m; ++i) {
			start[l[i]].push_back(i);
			end[r[i]].push_back(i);
		}
		std::map<int, ll> map;
		std::multiset<int> alive;
		for (const auto i: start[0]) {
			map[y[i]] = y[i];
			alive.insert(y[i]);
		}
		for (int i = 1; i < n; ++i) {
			for (const auto j: start[i]) {
				if (alive.find(y[j]) == alive.end()) {
					auto itr = map.lower_bound(y[j]);	
					ll d = INF;
					if (itr != map.end() and h[i] >= itr -> first) {
						d = std::min(d, itr -> second + (itr -> first - y[j]));
					}
					if (itr != map.begin()) {
						--itr;
						d = std::min(d, itr -> second + (y[j] - itr -> first));
					}
					map.emplace(y[j], d);
				}
				alive.insert(y[j]);
			}
			if (i != n - 1) {
				for (const auto j: end[i]) {
					alive.erase(alive.find(y[j]));
					if (alive.find(y[j]) == alive.end()) {
						map.erase(y[j]);
					}
				}
			}
		}
		ll ret = INF;
		for (const auto [y, d]: map) {
			ret = std::min(ret, y + d);
		}
		return (ret == INF ? -1  : ret + (x[n - 1] - x[0]));
	}
	return -1;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 14
• Subtask 3: 15 / 15
• Subtask 4: 0 / 18
• Subtask 5: 0 / 43