Submission #1062291

#	Time	Username	Problem	Language	Result	Execution time	Memory
1062291		nightfal	Stations (IOI20_stations)	C++17	13 / 100	626 ms	776 KiB

stations

#include <vector>
#include <iostream>
using namespace std;

template <typename T> void print(T elem) {cout << elem << " ";}
template <typename T> void print(vector<T> &v) {for(auto elem: v) print(elem); cout << endl;}
template <typename T> void print(vector<vector<T>> &v) {for(auto elem: v) print(elem); cout << endl;}

void makeG(vector<vector<int>> &g, vector<int> &u, vector<int> &v) {
	for(int i=0; i<u.size(); i++) {
		g[u[i]].push_back(v[i]);
		g[v[i]].push_back(u[i]);
	}
}
int decideSubtaskLabel(int n, int k, vector<vector<int>> &g, vector<int> &u, vector<int> &v) {
	int cnt = 0;
	for(int i=0; i<n; i++)
		if (g[i].size()>2) cnt++;
	if (cnt==0) return 1;

	bool subtask2 = true;
	for(int i=0; i<u.size(); i++)
		if (!(u[i]==i+1 && v[i]==i/2 || u[i]==i/2 && v[i]==i+1)) subtask2= false;
	if (subtask2) return 2;

	if (cnt==1) return 3;
}
void subtask1Label(int n, vector<vector<int>> &g, vector<int> &labels) {
	int node = 0;
	for(int i=0; i<n; i++)
		if(g[i].size()==1) node=i;

	int cnt = 0;
	while(labels[node]==-1) {
		labels[node] = cnt++; 
		for(int elem: g[node])
			if(labels[elem]==-1) node = elem;
	}
	return;
}
void subtask2Label(int n, vector<int> &labels) {
	for(int i=0; i<n; i++)
		labels[i] = i+1;
	return;
}
std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	vector<vector<int>> g(n);
	makeG(g,u,v);
	// print(g);
	int subtask = decideSubtaskLabel(n,k,g,u,v);
	vector<int> labels(n,-1);
	switch(subtask) {
		case 1: subtask1Label(n,g,labels); return labels;
		case 2: subtask2Label(n,labels); return labels;
		// case 2: 
		// case 3:
	}
}
int decideSubtaskFind(int s, int t, vector<int> &c) {

	for(int i=0; i<c.size(); i++)
		if (c[i] < s-1 || c[i] > s+1) return 2;
	return 1;
}
int subtask1Find(int s, int t, vector<int> &c) {
	if (c.size()==1) return c[0];
	else return t<s? c[0]:c[1];
}
bool ancestor(int a, int b) {
	if (a==0) return true;
	while(b!=0) { if(a==b) return true; else b >>= 1; }
	return false;
}
int subtask2Find(int s, int t, vector<int> &c) {
	for(int i=c.size()-1; i>=0; i--)
		if(ancestor(c[i],t)) return c[i];
	return c[0];
}
int find_next_station(int s, int t, std::vector<int> c) {
	int subtask = decideSubtaskFind(s,t,c);
	switch(subtask) {
		case 1: return subtask1Find(s,t,c);
		case 2: return subtask2Find(s,t,c);
	}
	return c[0];
}

Compilation message (stderr)

stations.cpp: In function 'void makeG(std::vector<std::vector<int> >&, std::vector<int>&, std::vector<int>&)':
stations.cpp:10:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |  for(int i=0; i<u.size(); i++) {
      |               ~^~~~~~~~~
stations.cpp: In function 'int decideSubtaskLabel(int, int, std::vector<std::vector<int> >&, std::vector<int>&, std::vector<int>&)':
stations.cpp:22:16: 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++)
      |               ~^~~~~~~~~
stations.cpp:23:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   23 |   if (!(u[i]==i+1 && v[i]==i/2 || u[i]==i/2 && v[i]==i+1)) subtask2= false;
stations.cpp: In function 'int decideSubtaskFind(int, int, std::vector<int>&)':
stations.cpp:61:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |  for(int i=0; i<c.size(); i++)
      |               ~^~~~~~~~~
stations.cpp: In function 'int decideSubtaskLabel(int, int, std::vector<std::vector<int> >&, std::vector<int>&, std::vector<int>&)':
stations.cpp:27:1: warning: control reaches end of non-void function [-Wreturn-type]
   27 | }
      | ^
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:47:25: warning: control reaches end of non-void function [-Wreturn-type]
   47 |  vector<vector<int>> g(n);
      |                         ^

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