Submission #669911

#	Time	Username	Problem	Language	Result	Execution time	Memory
669911		alvingogo	Towns (IOI15_towns)	C++14	0 / 100	22 ms	368 KiB

towns

#include <bits/stdc++.h>
#include <towns.h>
#pragma GCC optimize("Ofast")
#define AquA cin.tie(0);ios_base::sync_with_stdio(0);
#define fs first
#define sc second
#define p_q priority_queue
using namespace std;

map<pair<int,int>,int> mp;
int qt=0;
int f(int x,int y){
    if(x==y){
        return 0;
    }
    if(x>y){
        swap(x,y);
    }
    if(mp.find({x,y})!=mp.end()){
        return mp[{x,y}];
    }
    qt++;
    return mp[{x,y}]=getDistance(x,y);
}
int hubDistance(int n,int sub){
    mp.clear();
    int a=0;
    for(int i=0;i<n;i++){
        if(f(0,i)>f(0,a)){
            a=i;
        }
    }
    int b=a;
    for(int i=0;i<n;i++){
        if(f(a,i)>f(a,b)){
            b=i;
        }
    }
    assert(a!=b);
    map<int,pair<int,int> > m;
    for(int i=0;i<n;i++){
        if(i!=a && i!=b){
            int x=(f(a,i)-f(0,i)+f(a,0))/2;
            m[x].fs=max(m[x].fs,f(i,a)-x);
        }
    }
    vector<int> g;
    for(auto h:m){
        g.push_back(h.fs);
    }
    int p=g.size();
    vector<int> dis(p,0);
    for(int i=0;i<p;i++){
        dis[i]=max(dis[i],max(g[i],f(a,b)-g[i]));
        for(int j=i+1;j<p;j++){
            int u=g[j]-g[i];
            dis[i]=max(dis[i],m[g[j]].fs+u);
            dis[j]=max(dis[j],m[g[i]].fs+u);
        }
    }
    int y=0;
    for(int i=0;i<p;i++){
        if(dis[i]<dis[y]){
            y=i;
        }
    }
    vector<int> dis2(n);
    for(int i=0;i<n;i++){
        int x=(f(a,i)-f(0,i)+f(a,0))/2;
        dis2[i]=f(a,i)-x;
    }
    //assert(qt<=3*n);
    //cout << qt << endl;
    int at=1;
    vector<int> vis(n),pp(n);
    int cnt=0,lo=0;
    for(int i=0;i<n;i++){
        if(cnt==0){
            lo=i;
            cnt++;
        }
        else{
            if(f(lo,i)!=dis2[i]+dis2[lo]){
                cnt++;
                vis[i]=1;
                pp[lo]++;
            }
            else{
                cnt--;
            }
        }
    }
    int cc=0;
    for(int i=0;i<n;i++){
        if(!vis[i]){
            int q=(f(lo,i)!=dis2[i]+dis2[lo]);
            if(q){
                cc+=pp[i]+1;   
            }
        }
    }
    if(cc>n/2){
        at=-1;
    }
    return dis[y]*at;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:51:17: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   51 |     int p=g.size();
      |           ~~~~~~^~
towns.cpp:25:27: warning: unused parameter 'sub' [-Wunused-parameter]
   25 | int hubDistance(int n,int sub){
      |                       ~~~~^~~

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