Submission #210977

#	Time	Username	Problem	Language	Result	Execution time	Memory
210977		autumn_eel	Towns (IOI15_towns)	C++14	48 / 100	31 ms	1024 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
#define rep(i,n)for(int i=0;i<(n);i++)
using namespace std;

int d[150][150];
int dist(int i,int j){
	if(i==j)return 0;
	if(i>j)swap(i,j);
	if(d[i][j]!=-1)return d[i][j];
	int x=getDistance(i,j);
	return d[i][j]=x;
}

int hubDistance(int N, int sub) {
	memset(d,-1,sizeof(d));
	int Max=0,s=-1;
	rep(i,N){
		if(Max<dist(0,i)){
			Max=dist(0,i);
			s=i;
		}
	}
	Max=0;int t=-1;
	rep(i,N){
		if(Max<dist(s,i)){
			Max=dist(s,i);
			t=i;
		}
	}
	int Min=INT_MAX;
	set<int>idx;
	map<int,vector<int>>mp;
	rep(i,N){
		int x=dist(s,i),y=dist(t,i);
		int z=(x+y-Max)/2;
		int a=x-z,b=y-z;
		mp[a].push_back(i);
		if(Min>max(a,b)){
			Min=max(a,b);
			idx.clear();
		}
		if(Min==max(a,b)){
			idx.insert(a);
		}
	}
	if(sub<=2)return Min;
	auto C=[&](int id){
		int c1=0,c2=0;
		for(auto p:mp){
			if(p.first<id)c1+=p.second.size();
			if(p.first>id)c2+=p.second.size();
		}
		if(c1>N/2||c2>N/2)return false;
		vector<vector<int>>vs;
		for(int v:mp[id]){
			bool flag=false;
			for(auto&V:vs){
				if(dist(s,V[0])+dist(s,v)-2*id!=dist(V[0],v)){
					V.push_back(v);flag=true;
					if(V.size()>N/2)return false;
					break;
				}
			}
			if(!flag)vs.push_back({v});
		}
		return true;
	};

	for(int id:idx){
		if(C(id))return Min;
	}
	return -Min;
}

Compilation message (stderr)

towns.cpp: In lambda function:
towns.cpp:51:36: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
    if(p.first<id)c1+=p.second.size();
                                    ^
towns.cpp:52:36: warning: conversion to 'int' from 'std::vector<int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
    if(p.first>id)c2+=p.second.size();
                                    ^
towns.cpp:61:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      if(V.size()>N/2)return false;
         ~~~~~~~~^~~~

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