Submission #497822

#	Time	Username	Problem	Language	Result	Execution time	Memory
497822		MilosMilutinovic	기지국 (IOI20_stations)	C++14	0 / 100	753 ms	704 KiB

stations

#include <bits/stdc++.h>

using namespace std;

const int N = 1005;
const int L = 10;

int par[N][L], dep[N];
std::vector<int> G[N];

void dfs_init(int u, int p) {
	par[u][0] = p;
	for (int i = 1; i < L; ++i)
		if (par[u][i - 1] != -1)
			par[u][i] = par[par[u][i - 1]][i - 1];
	for (int v : G[u])
		if (v != p)
			dep[v] = dep[u] + 1, dfs_init(v, u);
}

int lca(int u, int v) {
	if (dep[u] < dep[v]) swap(u, v);
	for (int i = L - 1; ~i; --i)
		if (par[u][i] != -1 && dep[par[u][i]] >= dep[v])
			u = par[u][i];
	if (u == v) return u;
	for (int i = L - 1; ~i; --i)
		if (par[u][i] != par[v][i])
			u = par[u][i], v = par[v][i];
	return (u == v ? u : par[u][0]);
}

int n;
std::vector<int> vec;

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	::n = n;
	for (int i = 0; i < n - 1; ++i) {
		G[u[i]].push_back(v[i]);
		G[v[i]].push_back(u[i]);
	}

	int root = 0;
	for (int i = 0; i < n; ++i) {
		if (G[i].size() == 1) {
			root = i;
		}
	}

	function<void(int, int)> Dfs = [&](int u, int p) {
		vec.push_back(u);
		if (vec.size() >= n) return;
		for (int v : G[u]) {
			if (v == p) continue;
			Dfs(v, u);
		}
	};

	Dfs(root, -1);

	//dfs_init(0, -1);

	std::vector<int> l(n);
	iota(l.begin(), l.end(), 0);
	return l;
}

int find_next_station(int s, int t, std::vector<int> c) {
	//assert(s < n && t < n);
	/*std::vector<int> path;
	int l = lca(s, t);
	while (s != -1 && dep[s] >= dep[l]) {
		path.push_back(s);
		s = par[s][0];
	}
	while (t != -1 && dep[t] >= dep[l]) {
		path.push_back(t);
		t = par[t][0];
	}
	int node = 0;
	for (int i : path) for (int j : c)
		if (i == j) node = j;
	return node;*/
	int pos_s = -1, pos_t = -1;
	for (int i = 0; i < vec.size(); i++) {
		if (vec[i] == s) pos_s = i;
		if (vec[i] == t) pos_t = i;
	}

	if (pos_s == -1 || pos_t == -1) return c[0];

	std::vector<int> path;
	for (int i = pos_s; i <= pos_t; i++) {
		path.push_back(vec[i]);
	}
	for (int i = pos_t; i <= pos_s; i++) {
		path.push_back(vec[i]);
	}

	/*int node = 0;
	for (int i : path) for (int j : c)
		if (i == j) node = j;*/
	return c[0];
}

Compilation message (stderr)

stations.cpp: In lambda function:
stations.cpp:52:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   52 |   if (vec.size() >= n) return;
      |       ~~~~~~~~~~~^~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:85:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |  for (int i = 0; i < vec.size(); i++) {
      |                  ~~^~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61