제출 #771237

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
771237		SamNguyen	Robot (JOI21_ho_t4)	C++14	34 / 100	3085 ms	28136 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using lli = long long;
 
template <class T> 
using min_priority_queue = priority_queue<T, vector<T>, greater<T>>;
 
const lli INF = 0x1f1f1f1f1f1f1f1f;
const int MAX_N = 1e5 + 7;
const int MAX_M = 2e5 + 7;
 
template <class T1, class T2>
inline constexpr bool minimise(T1 &x, T2 y) {
	if (x > y) { x = y; return true; }
	return false;
}
 
class Edge {
private:
	int u, v, c;
	lli w;
 
public:
	Edge(int u = 0, int v = 0, int c = 0, lli w = 0): u(u), v(v), c(c), w(w) {}
 
	inline lli cost() const { return w; }
	inline pair<int, int> nodes() const { return make_pair(u, v); }
	inline int other_node(int z) const { return u ^ v ^ z; }
	inline int colour() const { return c; }
 
	inline int get_node(bool is_rev) const { return is_rev ? v : u; }
	inline bool is_start(int z) const { return z == u; }
};
 
int N, M;
Edge edge[MAX_M];
vector<int> adj[MAX_N];
 
void input() {
	cin >> N >> M;
	for (int i = 0; i < M; i++) {
		int u, v, c; lli w;
		cin >> u >> v >> c >> w;
		edge[i] = Edge(u, v, c, w);
		adj[u].push_back(i);
		adj[v].push_back(i);
	}
 
	edge[M] = Edge(0, 1, M + 1, 0);
}
 
lli dist[MAX_M][2][2];
bool is_locked[MAX_M][2][2];
 
min_priority_queue<tuple<lli, int, bool, bool>> pq;
lli sum_colour[MAX_M];
 
lli solve() {
	memset(dist, 0x1f, sizeof dist);
	memset(is_locked, false, sizeof is_locked);
	memset(sum_colour, 0, sizeof sum_colour);
 
	auto relax = [&](int i, bool is_rev, bool is_prev_mod, lli d) {
		if (minimise(dist[i][is_rev][is_prev_mod], d))
			pq.emplace(d, i, is_rev, is_prev_mod);
	};
 
	relax(M, 0, 0, 0);
 
	lli ans = INF;
	while (not pq.empty()) {
		lli cur_dist; int i; bool is_rev, is_prev_mod;
		tie(cur_dist, i, is_rev, is_prev_mod) = pq.top();
		pq.pop();
 
		int v = edge[i].get_node(not is_rev);
		if (v == N) 
			minimise(ans, cur_dist);
 
		if (is_locked[i][is_rev][is_prev_mod])
			continue;
		is_locked[i][is_rev][is_prev_mod] = true;
 
		for (int j : adj[v]) {
			if (j == i and is_prev_mod)
				continue;
 
			int c = edge[j].colour();
			sum_colour[c] += edge[j].cost();
		}
 
		for (int j : adj[v]) {
			int c = edge[j].colour();
			lli w = edge[j].cost();
			bool new_is_rev = not edge[j].is_start(v);
 
			if (sum_colour[c] == w)
				relax(j, new_is_rev, false, cur_dist);
 
			relax(j, new_is_rev, true, cur_dist + w);
			relax(j, new_is_rev, false, cur_dist + sum_colour[c] - w);
		}
 
		for (int j : adj[v]) {
			int c = edge[j].colour();
			sum_colour[c] = 0;
		}
	}
 
	if (ans >= INF)
		ans = -1;
	return ans;
}
 
int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
 
	input();
	cout << solve();
 
	return 0;
}

• Subtask 1: 34 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42