Submission #772683

#	Time	Username	Problem	Language	Result	Execution time	Memory
772683		khshg	Stations (IOI20_stations)	C++14	100 / 100	770 ms	940 KiB

stations

#include"stations.h"
#include<bits/stdc++.h>
using namespace std;
 
vector<vector<int>> adj;
int hi;
vector<int> L, R;
vector<bool> flor;
 
void dfs(int s, int p, bool flr) {
	flor[s] = flr;
	bool leaf = 1;
	if(!flr) {
		L[s] = ++hi;
	}
	for(auto& u : adj[s]) {
		if(u == p) continue;
		leaf = 0;
		dfs(u, s, flr ^ 1);
	}
	if(flr) {
		R[s] = ++hi;
	}
}
 
vector<int> label(int N, int K, vector<int> u, vector<int> v) {
	hi = -1;
	flor.resize(N);
	L.resize(N);
	R.resize(N);
	adj.resize(N);
	for(auto& I : adj) I.clear();
	for(int i = 0; i < (int)u.size(); ++i) {
		adj[u[i]].push_back(v[i]);
		adj[v[i]].push_back(u[i]);
	}
	dfs(0, -1, 0);
	vector<int> labels(N);
	for(int i = 0; i < N; ++i) labels[i] = (flor[i] ? R[i]: L[i]);
	return labels;
}
 
int find_next_station(int s, int t, vector<int> c) {
	if(s == 0) {
		pair<int, int> T = {t, t};
		vector<pair<int, int>> C((int)c.size());
		C[0] = {1, c[0]};
		for(int i = 1; i < (int)c.size(); ++i) {
			C[i] = {c[i - 1] + 1, c[i]};
		}
		for(int i = 0; i < (int)c.size(); ++i) {
			if(C[i].first <= T.second && C[i].second >= T.second) return c[i];
		}
	}
	if(s < c[0]) {
		pair<int, int> S = {s, c.back() - 1}, T = {t, t};
		vector<pair<int, int>> C((int)c.size());
		C[0] = {s + 1, c[0]};
		C.back() = {s, c.back()};
		for(int i = 1; i + 1 < (int)c.size(); ++i) {
			C[i] = {c[i - 1] + 1, c[i]};
		}
		for(int i = 0; i + 1 < (int)c.size(); ++i) {
			if(C[i].first <= T.second && C[i].second >= T.second) return c[i];
		}
		return c.back();
	}
	pair<int, int> S = {c[0] + 1, s}, T = {t, t};
	vector<pair<int, int>> C((int)c.size());
	C.back() = {c.back(), s - 1};
	C[0] = {c[0], s};
	for(int i = 1; i + 1 < (int)c.size(); ++i) {
		C[i] = {c[i], c[i + 1] - 1};
	}
	for(int i = 1; i < (int)c.size(); ++i) {
		if(C[i].first <= T.second && C[i].second >= T.second) return c[i];
	}
	return c[0];
}

Compilation message (stderr)

stations.cpp: In function 'void dfs(int, int, bool)':
stations.cpp:12:7: warning: variable 'leaf' set but not used [-Wunused-but-set-variable]
   12 |  bool leaf = 1;
      |       ^~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:56:18: warning: variable 'S' set but not used [-Wunused-but-set-variable]
   56 |   pair<int, int> S = {s, c.back() - 1}, T = {t, t};
      |                  ^
stations.cpp:68:17: warning: variable 'S' set but not used [-Wunused-but-set-variable]
   68 |  pair<int, int> S = {c[0] + 1, s}, T = {t, t};
      |                 ^

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