Submission #1026326

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026326		boyliguanhan	Towns (IOI15_towns)	C++17	100 / 100	15 ms	1248 KiB

towns

#include "towns.h"
#include<bits/stdc++.h>
using namespace std;
int Ddis[201][201];
inline int getD(int a,int b){
    if(a==b)return 0;
    if(a>b)swap(a,b);
    if(Ddis[a][b])
        return Ddis[a][b];
    return Ddis[a][b]=getDistance(a,b);
}
pair<int,int> mnn[200];
bool samesub(int a,int b){
    auto[i1,d1]=mnn[a];
    auto[i2,d2]=mnn[b];
    return getD(i1,i2)<d1+d2;
}
map<int,int>mp2;
int ok(map<int,vector<pair<int,int>>>mp,int pivot,int sub){
    mp2.clear();
    int toleft=0,toright=0,tot=0;
    vector<pair<int,int>> Tis;
    for(auto [i,x]:mp){tot+=x.size();
        if(i<pivot) toleft+=x.size();
        else if(i==pivot) Tis=x;
        else toright+=x.size();}
    for(auto[i,k]:Tis)
        mnn[i]={i,k};
    if(toleft>tot/2||toright>tot/2)
        return 0;
    if(Tis.size()<=tot/2)
        return 1;
    int cnt=0,bk=0;
    for(auto [i,K]:Tis){
        if(!cnt){
            mp2[i]=1;
            bk=i;
            cnt=i;
        } else {
            if(samesub(bk,i)){
                mp2[bk]++;
                cnt++;
            } else {
                cnt--;
                mp2[i]=1;
            }
        }
    }
    int asthis=0;
    for(auto[kk,kkk]:mp2)
        if(samesub(bk,kk))
            asthis+=samesub(kk,bk)*kkk;
    return asthis<=tot/2;
}
int hubDistance(int N, int sub) {
    memset(Ddis,0,sizeof Ddis);
    int pivot=0;
    int farnod=pivot,fardis=0;
    for(int i=0;i<N;i++)
        if(getD(i,pivot)>fardis)
            farnod=i,fardis=getD(i,pivot);
    fardis=0;
    int X=farnod;
    for(int i=0;i<N;i++)
        if(getD(i,X)>fardis)
            farnod=i,fardis=getD(i,X);
    int Y=farnod,K=fardis;
    map<int,vector<pair<int,int>>> mp;
    for(int i=0;i<N;i++){
        int toX=getD(X,i),toY=getD(pivot,i);
        int dep=(toX+toY-getD(pivot,X))/2;
        int distofP=getD(pivot,X)+toX-toY;
        mp[distofP].push_back({i,dep});
    }
    int candidate2=mp.lower_bound(K)->first,candidate1=(--mp.lower_bound(K))->first;
    int R;
    if(K-candidate1<candidate2-K){
        R=K-candidate1/2;
        if(!ok(mp,candidate1,sub&1))
            R=-R;
    } else if(K-candidate1>candidate2-K){
        R=candidate2/2;
        if(!ok(mp,candidate2,sub&1))
            R=-R;
    } else {
        R=candidate2/2;
        if(!ok(mp,candidate1,sub&1)&&
            !ok(mp,candidate2,sub&1))
            R=-R;
    }
    return R;
}

Compilation message (stderr)

towns.cpp: In function 'int ok(std::map<int, std::vector<std::pair<int, int> > >, int, int)':
towns.cpp:23:36: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   23 |     for(auto [i,x]:mp){tot+=x.size();
      |                                    ^
towns.cpp:24:36: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   24 |         if(i<pivot) toleft+=x.size();
      |                                    ^
towns.cpp:26:30: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   26 |         else toright+=x.size();}
      |                              ^
towns.cpp:31:18: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   31 |     if(Tis.size()<=tot/2)
      |        ~~~~~~~~~~^~~~~~~
towns.cpp:19:55: warning: unused parameter 'sub' [-Wunused-parameter]
   19 | int ok(map<int,vector<pair<int,int>>>mp,int pivot,int sub){
      |                                                   ~~~~^~~
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:67:9: warning: unused variable 'Y' [-Wunused-variable]
   67 |     int Y=farnod,K=fardis;
      |         ^

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