제출 #1087191

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1087191		guagua0407	도시들 (IOI15_towns)	C++17	0 / 100	10 ms	348 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

map<pair<int,int>,int> mpp;

int get(int a,int b){
    if(a>b) swap(a,b);
    if(mpp.find({a,b})!=mpp.end()) return mpp[{a,b}];
    else{
        mpp[{a,b}]=getDistance(a,b);
        return mpp[{a,b}];
    }
}

int hubDistance(int N, int sub) {
	int n=N;
    vector<int> dis(n);
    for(int i=0;i<n;i++){
        dis[i]=get(0,i);
    }
    int x=max_element(all(dis))-dis.begin();
    for(int i=0;i<n;i++){
        dis[i]=get(x,i);
    }
    int y=max_element(all(dis))-dis.begin();
    vector<int> dis2(n);
    for(int i=0;i<n;i++){
        dis2[i]=get(y,i);
    }
    vector<int> val1(n),val2(n);
    vector<int> vec;
    for(int i=0;i<n;i++){
        vec.push_back(dis[i]-(dis[i]+dis2[i]-dis[y])/2);
        val1[i]=dis[i]-(dis[i]+dis2[i]-dis[y])/2;
        val2[i]=(dis[i]+dis2[i]-dis[y])/2;
    }
    sort(all(vec));
    int R=dis[y];
    int ans=R;
    for(auto v:vec){
        ans=min(ans,max(v,R-v));
    }
    map<int,int> mp;
    for(auto v:vec){
        mp[v]++;
    }
    bool tf=false;
    int pre=0;
    for(auto v:mp){
        if(max(v.f,R-v.f)==ans){
            int mx=max({pre,v.s,n-pre-v.s});
            if(mx<=n/2){
                tf=true;
            }
        }
        pre+=v.s;
    }
    int prv=ans;
    function<bool(int,int)> same=[&](int a,int b){
        int d=get(a,b);
        return (d==(val2[a]+val2[b]));
    };
    if(!tf){
        pre=0;
        for(auto v:mp){
            if(max(v.f,R-v.f)==ans){
                if(v.s>n/2){
                    vector<int> xs;
                    for(int i=0;i<n;i++){
                        if(val1[i]==v.f){
                            xs.push_back(i);
                        }
                    }
                    vector<pair<int,int>> diaob;
                    vector<pair<int,int>> roy;
                    for(auto u:xs){
                        diaob.push_back({u,1});
                    }
                    while((int)diaob.size()>1){
                        vector<pair<int,int>> tmp;
                        for(int i=0;i<(int)diaob.size()-1;i+=2){
                            if(diaob[i].s<diaob[i+1].s) swap(diaob[i],diaob[i+1]);

                            if(same(diaob[i].f,diaob[i+1].f)){
                                tmp.push_back({diaob[i].f,diaob[i].s+diaob[i+1].s});
                            }
                            else{
                                roy.push_back({diaob[i].f,diaob[i+1].s});
                                roy.push_back({diaob[i+1].f,diaob[i+1].s});
                                if(diaob[i].s>diaob[i+1].s) tmp.push_back({diaob[i].f,diaob[i].s-diaob[i+1].s});
                            }
                        }
                        if((int)diaob.size()%2==1){
                            tmp.push_back(diaob.back());
                        }
                        diaob=tmp;
                    }
                    if(diaob.empty()){
                        tf=true;
                        break;
                    }
                    int cnt=diaob[0].s;
                    int node=diaob[0].f;
                    for(auto u:roy){
                        if(same(node,u.f)) cnt+=u.s;
                    }
                    if(cnt>n/2){
                        tf=false;
                    }
                    else{
                        tf=true;
                    }
                    break;
                }
            }
            pre+=v.s;
        }
    }
	return (tf?ans:-ans);
}

컴파일 시 표준 에러 (stderr) 메시지

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:28:32: warning: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
   28 |     int x=max_element(all(dis))-dis.begin();
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
towns.cpp:32:32: warning: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
   32 |     int y=max_element(all(dis))-dis.begin();
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
towns.cpp:65:9: warning: unused variable 'prv' [-Wunused-variable]
   65 |     int prv=ans;
      |         ^~~
towns.cpp:22:28: warning: unused parameter 'sub' [-Wunused-parameter]
   22 | int hubDistance(int N, int sub) {
      |                        ~~~~^~~

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