Submission #669996

#	Time	Username	Problem	Language	Result	Execution time	Memory
669996		alvingogo	Towns (IOI15_towns)	C++14	0 / 100	42 ms	652 KiB

towns

#include <bits/stdc++.h>
#include "towns.h"
#define fs first
#define sc second
using namespace std;

map<pair<int,int>,int> mpaa;
int qt=0;
int f(int x,int y){
    if(x==y){
        return 0;
    }
    if(x>y){
        swap(x,y);
    }
    if(mpaa.find(pair<int,int>(x,y))!=mpaa.end()){
        return mpaa[pair<int,int>(x,y)];
    }
    qt++;
    return mpaa[pair<int,int>(x,y)]=getDistance(x,y);
}
int hubDistance(int n, int sub) {
    mpaa.clear();
    vector<int> dist0(n);
    for (int i = 1; i < n; ++i) {
        dist0[i] = f(0,i);
    }
 
    int a = max_element(dist0.begin(), dist0.end()) - dist0.begin();
 
    vector<int> dist(n);
    dist[0] = dist0[a];
    for (int i = 1; i < n; ++i) {
        dist[i] = i == a ? 0 : f(i, a);
    }
 
    int b = max_element(dist.begin(), dist.end()) - dist.begin();
 
    vector<int> pos(n);
    pos[0] = (dist0[a] - dist0[b] + dist[b]) >> 1;
    for (int i = 1; i < n; ++i) {
        pos[i] = min(pos[0], (dist0[a] - dist0[i] + dist[i]) >> 1);
    }
 
    int ans = numeric_limits<int>::max();
 
    map<int, vector<int>> mp;
    int mss=0;
    for (int i = 0; i < n; ++i) {
        if(max(pos[i], dist[b] - pos[i])>ans){
            ans = min(ans, max(pos[i], dist[b] - pos[i]));
            mss=pos[i];
        }
        
        mp[pos[i]].push_back(i);
    }
    vector<int> dis2(n);
    for(auto h:mp){
        for(auto z:h.sc){
            dis2[z]=f(a,z)-pos[z]+abs(mss-h.fs);
        }
    }
    int at=1;
    vector<int> vis(n),pp(n);
    int cnt=0,lo=0;
    
    for(int i=0;i<n;i++){
        int u=0;
        for(int j=0;j<n;j++){
            if(f(i,j)!=dis2[i]+dis2[j]){
                u++;
            }
        }
        if(u>n/2){
            at=-1;
        }
        //cout << i << " " << u << "\n";
    }
    return at*ans;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:29:53: warning: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
   29 |     int a = max_element(dist0.begin(), dist0.end()) - dist0.begin();
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
towns.cpp:37:51: warning: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
   37 |     int b = max_element(dist.begin(), dist.end()) - dist.begin();
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
towns.cpp:65:9: warning: unused variable 'cnt' [-Wunused-variable]
   65 |     int cnt=0,lo=0;
      |         ^~~
towns.cpp:65:15: warning: unused variable 'lo' [-Wunused-variable]
   65 |     int cnt=0,lo=0;
      |               ^~
towns.cpp:22:28: warning: unused parameter 'sub' [-Wunused-parameter]
   22 | 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