Submission #1036682

#	Time	Username	Problem	Language	Result	Execution time	Memory
1036682		vjudge1	Towns (IOI15_towns)	C++17	48 / 100	65 ms	25428 KiB

towns

#include "towns.h"

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

int n;

int dist[200][200];

const int lim=1e6+100;

int pref[lim],suf[lim];
vector<int>blw[lim];

int query(int i,int j){
	if(j<i)swap(i,j);
	if(!dist[i][j])dist[i][j]=getDistance(i,j);
	return dist[i][j];
}

int hubDistance(int N, int sub) {
	for(int i=0;i<=1000000;i++)blw[i].clear();
	memset(dist,0,sizeof(dist));
	n=N;
	int past=-1,point1=-1;
	for(int i=1;i<n;i++){
		if(past<query(0,i)){
			point1=i;
			past=query(0,i);
		}
	}
	past=-1;
	int point2=-1;
	for(int i=0;i<n;i++){
		if(i==point1)continue;
		if(past<query(point1,i)){
			point2=i;
			past=query(point1,i);
		}
	}
	int ds=query(point1,point2);
	int ans=1e9;
	for(int i=0;i<n;i++){
		if(i==point1||i==point2)continue;
		int tem=(query(point1,i)+query(point2,i)-ds)/2;
		int val1=query(point1,i)-tem;
		int val2=query(point2,i)-tem;
		//cerr<<val1<<" "<<val2<<" ?\n";
		blw[val1].push_back(i);
		ans=min(ans,max({tem,val1,val2}));
	}
	int dude1=ans,dude2=ds-ans;
	ans=-ans;
	pref[0]=1;
	suf[ds]=1;
	for(int i=1;i<=ds;i++){
		pref[i]=pref[i-1]+blw[i].size();
		suf[ds-i]=suf[ds-i+1]+blw[ds-i].size();
	}
	for(int dude:{dude1,dude2}){
		if(!blw[dude].size())continue;
		if(n/2<pref[dude-1]||n/2<suf[dude+1])continue;
		if(n/2<blw[dude].size()){
			if(sub!=3)continue;
			bool nope=0;
			for(int i=0;i<blw[dude].size();i++){
				int cnt=1;
				int tem1=(query(point1,blw[dude][i])+query(point2,blw[dude][i])-ds)/2;
				for(int j=0;j<blw[dude].size();j++){
					if(i==j)continue;
					int tem2=(query(point1,blw[dude][j])+query(point2,blw[dude][j])-ds)/2;
					if(tem1+tem2!=query(blw[dude][j],blw[dude][i]))cnt++;
				}
				if(n/2<cnt){
					nope=1;
					break;
				}
			}
			if(nope)continue;
		}
		ans=abs(ans);
	}
	return ans;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:57:20: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   57 |   pref[i]=pref[i-1]+blw[i].size();
      |           ~~~~~~~~~^~~~~~~~~~~~~~
towns.cpp:58:24: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   58 |   suf[ds-i]=suf[ds-i+1]+blw[ds-i].size();
      |             ~~~~~~~~~~~^~~~~~~~~~~~~~~~~
towns.cpp:63:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |   if(n/2<blw[dude].size()){
      |      ~~~^~~~~~~~~~~~~~~~~
towns.cpp:66:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |    for(int i=0;i<blw[dude].size();i++){
      |                ~^~~~~~~~~~~~~~~~~
towns.cpp:69:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |     for(int j=0;j<blw[dude].size();j++){
      |                 ~^~~~~~~~~~~~~~~~~

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