Submission #614545

#	Time	Username	Problem	Language	Result	Execution time	Memory
614545		penguinhacker	Stations (IOI20_stations)	C++17	100 / 100	855 ms	900 KiB

stations

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

const int mxN=1000;
int n, tin[mxN], tout[mxN], t, d[mxN];
vector<int> adj[mxN];

void dfs(int u=0, int p=-1) {
	tin[u]=t++;
	for (int v : adj[u])
		if (v!=p) {
			d[v]=d[u]+1;
			dfs(v, u);
		}
	tout[u]=t++;
}

vector<int> label(int _n, int _k, vector<int> u, vector<int> v) {
	n=_n;
	for (int i=0; i<n; ++i)
		adj[i].clear();
	for (int i=0; i<n-1; i++) {
		adj[u[i]].push_back(v[i]);
		adj[v[i]].push_back(u[i]);
	}
	dfs();
	vector<int> inds(n), labels(n);
	iota(inds.begin(), inds.end(), 0);
	sort(inds.begin(), inds.end(), [](int a, int b) { return (d[a]%2?tout[a]:tin[a])<(d[b]%2?tout[b]:tin[b]); });
	for (int i=0; i<n; ++i)
		labels[inds[i]]=i;
	/*for (int i : labels)
		cout << i << " ";
	cout << endl;*/
	return labels;
}

int find_next_station(int s, int t, vector<int> c) {
	if (c.back()>s) { // s is tin[s]
		if (!s||s<=t&&t<=c.end()[-2]) { // t is in subtree of s
			for (int i=0; i+(s>0)<c.size(); ++i)
				if (t<=c[i])
					return c[i];
			assert(0);
		} else
			return c.back();
	} else {
		if (c.size()>1&&c[1]<=t&&t<=s) { // again in subtree
			for (int i=c.size()-1; i; --i)
				if (t>=c[i])
					return c[i];
			assert(0);
		} else
			return c[0];
	}
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:41:15: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   41 |   if (!s||s<=t&&t<=c.end()[-2]) { // t is in subtree of s
stations.cpp:42:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |    for (int i=0; i+(s>0)<c.size(); ++i)
      |                  ~~~~~~~^~~~~~~~~

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