Submission #361951

#	Time	Username	Problem	Language	Result	Execution time	Memory
361951		usuyus	Stations (IOI20_stations)	C++14	100 / 100	995 ms	1352 KiB

stations

#include "stations.h"
#include <bits/stdc++.h>
#define N 1005
using namespace std;

vector<int> tree[N];

int dfs(int nd, int par, int cur, bool pre, vector<int> &labels) {
	if (pre) labels[nd] = cur++;
	
	for (int child : tree[nd]) {
		if (child == par) continue;
		cur = dfs(child, nd, cur, !pre, labels);
	}

	if (!pre) labels[nd] = cur++;
	return cur;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
	for (int i=0; i<n; i++) tree[i].clear();
	for (int i=0; i<u.size(); i++) {
		tree[u[i]].push_back(v[i]);
		tree[v[i]].push_back(u[i]);
	}

	vector<int> labels(n);
	dfs(0, -1, 0, 0, labels);
	return labels;
}

int find_next_station(int s, int t, vector<int> c) {
	sort(c.begin(), c.end());
	int sz = c.size();
	
	if (s == t) return s;
	if (sz == 1) return c[0];

	if (s < c[0]) { // s is preorder
		if (t < s || t > c[sz-2]) return c[sz-1]; // parent

		for (int i=0; i<sz; i++) {
			if (t <= c[i]) return c[i];
		}
	} else { // s is postorder
		if (t < c[1] || t > s) return c[0]; // parent

		for (int i=2; i<sz; i++) {
			if (t < c[i]) return c[i-1];
		}
		return c[sz-1];
	}

	return -1337; // it should not come here
}

Compilation message (stderr)

stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:22:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |  for (int i=0; i<u.size(); i++) {
      |                ~^~~~~~~~~

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