Submission #590916

#	Time	Username	Problem	Language	Result	Execution time	Memory
590916		FatihSolak	Towns (IOI15_towns)	C++17	48 / 100	21 ms	664 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
#define N 200
using namespace std;
int dist[N][N];
int get(int i,int j){
	if(i > j)swap(i,j);
	if(i == j)return 0;
	if(dist[i][j])return dist[i][j];
	return dist[i][j] = getDistance(i,j);
}
int cnt[N];
int child_cnt[N];
int hubDistance(int n, int sub) {
	for(int i = 0;i<n;i++){
		for(int j = 0;j<n;j++){
			dist[i][j] = 0;
		}
	}
	int root = 0;
	for(int i = 1;i<n;i++){
		if(get(0,i) > get(0,root))
			root = i;
	}
	int deepest = 0;
	for(int i = 1;i<n;i++){
		if(get(root,i) > get(root,deepest))
			deepest = i;
	}
	set<int> depths;
	map<int,int> mp;
	for(int i = 0;i<n;i++){
		depths.insert( (get(root,deepest) + get(root,i)  -get(deepest,i) )/2);
		mp[(get(root,deepest) + get(root,i)  -get(deepest,i) )/2]++;
	}
	int mini = 1e9;
	vector<int> v;
	for(auto u:depths){
		v.push_back(u);
		mini = min(mini,max(u,get(root,deepest)-u));
	}
	vector<int> candidates;
	for(int i = v.size()-1;i>=0;i--){
		cnt[i] = mp[v[i]];
		child_cnt[i] = 0;
		if(i+1 != v.size())
			child_cnt[i] = cnt[i+1];
		cnt[i] += child_cnt[i];
		//cout << v[i] << " "<< cnt[i] << endl;
		if(max(v[i],get(root,deepest)-v[i]) == mini && child_cnt[i] <= n/2 && (n - cnt[i]) <= n/2){
			candidates.push_back(i);
		}
	}
	int sign = 1;
	if(sub > 2){
		if(candidates.empty())sign = -1;
		if(candidates.size() == 1){
			if(sub == 4){
				if((n - child_cnt[candidates[0]] -  (n - cnt[candidates[0]])) > n/2)
					sign = -1;
			}
			else{
				vector<int> numbers;
				for(int i = 0;i<n;i++){
					if((get(root,deepest) + get(root,i)  -get(deepest,i) )/2 == v[candidates[0]]){
						numbers.push_back(i);
					}
				}
				int maxi = 0;
				for(auto u:numbers){
					int now = 0;
					for(auto c:numbers){
						if((get(root,u) + get(root,c)  -get(u,c) )/2 != v[candidates[0]]){
							now++;
						}
					}
					maxi = max(maxi,now);
				}
				if(maxi > n/2){
					sign = -1;
				}
			}
		}
	}
	return mini * sign;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:43:22: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   43 |  for(int i = v.size()-1;i>=0;i--){
      |              ~~~~~~~~^~
towns.cpp:46:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |   if(i+1 != v.size())
      |      ~~~~^~~~~~~~~~~

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