Submission #400259

#	Time	Username	Problem	Language	Result	Execution time	Memory
400259		bigg	Towns (IOI15_towns)	C++14	35 / 100	22 ms	396 KiB

towns

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

const int MAXN = 115;
const int INF  = 1e6;

int dista[MAXN][MAXN];
pair<int, int> p1, p2;
map<int, int > AB;
map<int, vector<int> > AB2;


int get(int a, int b){
	if(dista[a][b] != -1) return dista[a][b];
	dista[a][b] = dista[b][a] = getDistance(a,b);
	return dista[a][b];
}
int disttosv[MAXN];
int pai[MAXN], peso[MAXN];

int find(int x){
	if(pai[x] == x) return x;
	return pai[x] = find(pai[x]);
}

void join(int u, int v){
	u = find(u), v = find(v);
	if(u == v) return;
	if(peso[u] < peso[v]) swap(u,v);
	pai[v] = u;
	peso[u] += peso[v];
}

int hubDistance(int N, int sub) {
	p1 = {0,0};
	p2 = {0,0};
	AB.clear();
	AB2.clear();
	memset(dista, -1, sizeof(dista));
	memset(disttosv, 0, sizeof(disttosv));
	for(int i = 0; i < N; i++) pai[i] = i, peso[i] = 1;
	for(int i = 0; i < N; i++){
		int d = get(0, i);
		if(d > p1.second) p1 = {i,d};
	}	
	for(int i = 0; i < N; i++){
	
		int d = get(i, p1.first);
		if(d > p2.second) p2 = { i, d};
	}
	
	int ans = INF;
	int diam = get(p1.first, p2.first);
	for(int i = 0; i < N; i++) ans = min(ans, (diam + abs(get(p1.first, i) - get(p2.first, i)))/2);
	if(sub <= 2) return ans;
	for(int i = 0; i < N; i++){
		if(i == p1.first || i == p2.first) continue;
		int i1 = get(i, p1.first), i2 = get(i, p2.first);
		AB[i1 - (i1+i2-diam)/2]++;
		AB2[i1- (i1+i2-diam)/2].push_back(i);
		disttosv[i] = (i1+i2-diam)/2;
	}
	bool iscentroid = 0;
	if(sub == 4){
		int jacontei = 1;
		
		for(map<int,int> :: iterator it = AB.begin(); it != AB.end(); it++){
			if(it->first == ans || it->first == diam - ans){
				if(jacontei <= N/2 && N - jacontei - it->second <= N/2 && it->second <= N/2) iscentroid = 1;
			}
			jacontei += it->second;
		}
		
		if(!iscentroid) ans = -ans;

	} 
	if(sub == 3){
	
		int jacontei= 1;
		for(auto it : AB2){
			if(it.first != ans && it.first != diam - ans){
				jacontei += it.second.size();
				continue;
			}
			if(jacontei <= (N/2) && N- jacontei - it.second.size() <= N/2) iscentroid = 1;
			for(int i = 0; i < it.second.size(); i++){
				for(int j = i + 1; j < it.second.size(); j++){
					if(get(it.second[i], it.second[j]) != disttosv[it.second[i]] + disttosv[it.second[j]]) 
						join(it.second[i], it.second[j]);
				}
			}
			for(int i = 0; i < it.second.size(); i++) iscentroid &= (peso[find(it.second[i])] <= N/2);
			if(iscentroid) return ans;
			jacontei += it.second.size();
		}
		if(!iscentroid) ans = -ans;
		
	}     
	return ans;        
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:83:32: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   83 |     jacontei += it.second.size();
      |                                ^
towns.cpp:86:59: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   86 |    if(jacontei <= (N/2) && N- jacontei - it.second.size() <= N/2) iscentroid = 1;
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
towns.cpp:87:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |    for(int i = 0; i < it.second.size(); i++){
      |                   ~~^~~~~~~~~~~~~~~~~~
towns.cpp:88:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |     for(int j = i + 1; j < it.second.size(); j++){
      |                        ~~^~~~~~~~~~~~~~~~~~
towns.cpp:93:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |    for(int i = 0; i < it.second.size(); i++) iscentroid &= (peso[find(it.second[i])] <= N/2);
      |                   ~~^~~~~~~~~~~~~~~~~~
towns.cpp:95:31: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   95 |    jacontei += it.second.size();
      |                               ^

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