Submission #399951

#	Time	Username	Problem	Language	Result	Execution time	Memory
399951		peuch	Towns (IOI15_towns)	C++17	100 / 100	29 ms	1580 KiB

towns

#include "towns.h"
#include<bits/stdc++.h>
using namespace std;
 
const int MAXN = 310;
 
int dist[MAXN][MAXN];
int marc[MAXN][MAXN];
int morto[MAXN];
int p1, p2, n;
int cnt; 
 
int getD(int i, int j){
	if(marc[i][j]) return dist[i][j];
	marc[i][j] = marc[j][i] = 1;
	if(i == j) return dist[i][j] = dist[j][i] = 0;
//	printf("Asking: %d %d\n", i, j);
	cnt++;
	return dist[i][j] = dist[j][i] = getDistance(i, j);
}
 
int getSize(vector<int> grp, vector<int> test, int goal){
	int cnt1 = 1, cnt2 = 0;
	while(true){
		bool flag = true;
		int x;
		int id;
		for(int i = 0; i < grp.size(); i++){
			for(int j = 0; j < test.size(); j++){
				if(morto[test[j]]) continue;
				if(!marc[grp[i]][test[j]]) continue;
				flag = false;
				x = (getD(p1, grp[i]) + getD(p1, test[j]) - getD(grp[i], test[j])) / 2;
				id = j;
				break;
			}
			if(!flag) break;
		}
		if(flag){
			for(int j = 0; j < test.size(); j++){
				if(morto[test[j]]) continue;
				flag = false;
				x = (getD(p1, grp[0]) + getD(p1, test[j]) - getD(grp[0], test[j])) / 2;
				id = j;
				break;
			}
		}
		if(flag) break;
		if(x > goal) cnt1++, grp.push_back(test[id]);
		else cnt2++;
		morto[test[id]] = 1;
		if(cnt1 > n / 2 || cnt2 > n / 2) break;
	}
	return (cnt1 > n / 2) ? -1 : 1;
}
 
int hubDistance(int N, int sub) {
	srand(time(0));
	n = N;
	p1 = 0, p2 = 0;
	int maxi = 0;
	memset(dist, 0, sizeof(dist));
	memset(marc, 0, sizeof(marc));
	memset(morto, 0, sizeof(morto));
	cnt = 0;
	for(int i = 0; i < N; i++){
		int aux = getD(0, i);
		if(aux > maxi) p1 = i, maxi = aux;
	}
	maxi = 0;
	for(int i = 0; i < N; i++)
		if(getD(p1, i) > maxi) maxi = getD(p1, i), p2 = i;
	
	int diam = getD(p1, p2);
	int cruz0 = (diam + getD(p1, 0) - getD(p2, 0)) / 2;
	int ans = max(cruz0, diam - cruz0);
	for(int i = 0; i < N; i++){
		int x = (getD(p1, 0) + getD(p1, i) - getD(0, 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 = (getD(p1, 0) + getD(p1, i) - getD(0, 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;
	}
	random_shuffle(lMid.begin(), lMid.end());
	random_shuffle(rMid.begin(), rMid.end());
	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 = getD(p1, pilha.top());
				int x = (aux + getD(p1, lMid[i]) - getD(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();
		vector<int> grp;
		grp.push_back(k);
		morto[k] = 1;
		return getSize(grp, lMid, min(ans, diam - ans)) * 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 = getD(p1, pilha.top());
				int x = (aux + getD(p1, rMid[i]) - getD(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();
		vector<int> grp;
		grp.push_back(k);
		morto[k] = 1;
		return getSize(grp, rMid, max(ans, diam - ans)) * ans;
	}
	return ans;
}

Compilation message (stderr)

towns.cpp: In function 'int getSize(std::vector<int>, std::vector<int>, int)':
towns.cpp:28:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |   for(int i = 0; i < grp.size(); i++){
      |                  ~~^~~~~~~~~~~~
towns.cpp:29:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |    for(int j = 0; j < test.size(); j++){
      |                   ~~^~~~~~~~~~~~~
towns.cpp:40:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |    for(int j = 0; j < test.size(); j++){
      |                   ~~^~~~~~~~~~~~~
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:58:12: warning: conversion from 'time_t' {aka 'long int'} to 'unsigned int' may change value [-Wconversion]
   58 |  srand(time(0));
      |        ~~~~^~~
towns.cpp:94:52: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   94 |   if(lSize > N / 2 || rSize > N / 2 || lMid.size() > N / 2 || rMid.size() > N / 2) return -ans;
      |                                        ~~~~~~~~~~~~^~~~~~~
towns.cpp:94:75: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   94 |   if(lSize > N / 2 || rSize > N / 2 || lMid.size() > N / 2 || rMid.size() > N / 2) return -ans;
      |                                                               ~~~~~~~~~~~~^~~~~~~
towns.cpp:100:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  100 |  else if(lMid.size() > N / 2){
      |          ~~~~~~~~~~~~^~~~~~~
towns.cpp:102:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |   for(int i = 0; i < lMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~
towns.cpp:118:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  118 |  else if(rMid.size() > N / 2){
      |          ~~~~~~~~~~~~^~~~~~~
towns.cpp:120:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |   for(int i = 0; i < rMid.size(); i++){
      |                  ~~^~~~~~~~~~~~~

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