Submission #399730

#	Time	Username	Problem	Language	Result	Execution time	Memory
399730		peuch	Towns (IOI15_towns)	C++17	48 / 100	23 ms	904 KiB

towns

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

const int MAXN = 1e6;

int dist[3][MAXN];

int hubDistance(int N, int sub) {
	int p1 = 0, p2 = 0;
	int maxi = 0;
	for(int i = 0; i < N; i++){
		int aux = getDistance(0, i);
		if(aux > maxi) p1 = i, maxi = aux;
	}
	maxi = 0;
	for(int i = 0; i < N; i++){
		dist[0][i] = getDistance(p1, i);
		if(dist[0][i] > maxi) maxi = dist[0][i], p2 = i;
	}
	for(int i = 0; i < N; i++)
		dist[1][i] = getDistance(p2, i);
	
	int diam = dist[0][p2];
	int ans = MAXN;
	for(int i = 0; i < N; i++){
		int x = (diam + dist[0][i] - dist[1][i]) / 2;
		ans = min(ans, max(x, diam - x));
	}
	
	if(sub <= 2) return ans;
	
	int lSize = 0, rSize = 0;
	vector<int> lMid, rMid;
	for(int i = 0; i < N; i++){
		int x = (diam + dist[0][i] - dist[1][i]) / 2;
		if(x < min(ans, diam - ans)) lSize++;
		else if(x == min(ans, diam - ans)) lMid.push_back(i); 
		else if(x == max(ans, diam - ans)) rMid.push_back(i);
		else rSize++;
	}
	if(sub <= 4){
		if(lSize > N / 2 || rSize > N / 2 || lMid.size() > N / 2 || rMid.size() > N / 2) return -ans;
		return ans;
	}
	
	if(lSize > N / 2 || rSize > N / 2) return -ans;
	else if(lMid.size() > N / 2){
		stack<int> pilha;
		for(int i = 0; i < lMid.size(); i++){
			if(pilha.empty()) pilha.push(lMid[i]);
			else{
				int aux = dist[0][pilha.top()];
				int x = (aux + dist[0][lMid[i]] - getDistance(pilha.top(), lMid[i])) / 2;
				if(x == min(ans, diam - ans)) pilha.pop();
				else pilha.push(lMid[i]);
			}
		}
		if(pilha.empty()) return ans;
		int k = pilha.top();
		int cnt = 0;
		for(int i = 0; i < lMid.size(); i++){
			int aux = dist[0][k];
			int x = (aux + dist[0][lMid[i]] - getDistance(k, lMid[i])) / 2;
			if(x > min(ans, diam - ans)) cnt++;
		}
		if(cnt > N / 2) return -ans;
		return ans;
	}
	else if(rMid.size() > N / 2){
		stack<int> pilha;
		for(int i = 0; i < rMid.size(); i++){
			if(pilha.empty()) pilha.push(rMid[i]);
			else{
				int aux = dist[0][pilha.top()];
				int x = (aux + dist[0][rMid[i]] - getDistance(pilha.top(), rMid[i])) / 2;
				if(x == max(ans, diam - ans)) pilha.pop();
				else pilha.push(rMid[i]);
			}
		}
		if(pilha.empty()) return ans;
		int k = pilha.top();
		int cnt = 0;
		for(int i = 0; i < rMid.size(); i++){
			int aux = dist[0][k];
			int x = (aux + dist[0][rMid[i]] - getDistance(k, rMid[i])) / 2;
			if(x > max(ans, diam - ans)) cnt++;
		}
		if(cnt > N / 2) return -ans;
		return ans;
	}
	return ans;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:43:52: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   43 |   if(lSize > N / 2 || rSize > N / 2 || lMid.size() > N / 2 || rMid.size() > N / 2) return -ans;
      |                                        ~~~~~~~~~~~~^~~~~~~
towns.cpp:43:75: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   43 |   if(lSize > N / 2 || rSize > N / 2 || lMid.size() > N / 2 || rMid.size() > N / 2) return -ans;
      |                                                               ~~~~~~~~~~~~^~~~~~~
towns.cpp:48:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   48 |  else if(lMid.size() > N / 2){
      |          ~~~~~~~~~~~~^~~~~~~
towns.cpp:50:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |   for(int i = 0; i < lMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~
towns.cpp:62:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |   for(int i = 0; i < lMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~
towns.cpp:70:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   70 |  else if(rMid.size() > N / 2){
      |          ~~~~~~~~~~~~^~~~~~~
towns.cpp:72:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |   for(int i = 0; i < rMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~
towns.cpp:84:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   84 |   for(int i = 0; i < rMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 0 / 39