Submission #60174

#	Time	Username	Problem	Language	Result	Execution time	Memory
60174		istlemin	Towns (IOI15_towns)	C++14	0 / 100	37 ms	604 KiB

towns

#include "towns.h"
#include<bits/stdc++.h>

using namespace std;

#define rep(i,a,b) for(int i = a; i<int(b);++i)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define trav(a,c) for(auto a: c)

typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll,ll> pii;

ll n;

map<pii,ll> distMem;

ll distance(ll a,ll b){
    pii p = {min(a,b),max(a,b)};
    if(distMem.find(p)!=distMem.end()) return distMem[p];
    return distMem[p] = getDistance(a,b);
}

pii getFurthest(ll v){
	ll furthest = 0;
    ll mx = 0;
    rep(i,0,n){
		ll dist = distance(v,i);
        if(dist>mx){
            mx = dist;
            furthest = i;
        }
    }
    return {furthest,mx};
}

int hubDistance(int N, int sub) {
	n = N;
	ll diaA = getFurthest(0).first;
    pii tmp = getFurthest(diaA);
    ll diaB = tmp.first;
    ll diameter = tmp.second;

    map<ll,ll> pointsOnDiameter;

    rep(i,0,n){
        if(i==diaA||i==diaB) continue;

        ll distA = distance(i,diaA);
        ll distB = distance(i,diaB);

		ll distFromDiameter = (distA+distB-diameter)/2;

        pointsOnDiameter[distA-distFromDiameter]++;
    }

    ll minR = 1e18;
    ll center = 0;

    trav(x,pointsOnDiameter){
		ll currR = max(x.first,diameter-x.first);
		if(currR<minR){
            center = x.first;
            minR = currR;
		}
    }
    return minR;
    //if(pointsOnDiameter[center]<=n/2) return
}

Compilation message (stderr)

towns.cpp: In function 'll distance(ll, ll)':
towns.cpp:22:40: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
     return distMem[p] = getDistance(a,b);
                                        ^
towns.cpp:22:40: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:68:12: warning: conversion to 'int' from 'll {aka long long int}' may alter its value [-Wconversion]
     return minR;
            ^~~~
towns.cpp:59:8: warning: variable 'center' set but not used [-Wunused-but-set-variable]
     ll center = 0;
        ^~~~~~
towns.cpp:38:28: warning: unused parameter 'sub' [-Wunused-parameter]
 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