| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 592274 | Deepesson | Towns (IOI15_towns) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#define MAX 115
int getDistance(int i, int j);
int hubDistance(int N, int sub);
typedef std::pair<int,int> pii;
std::map<pii,int> memoria;
int count=0;
int smartgetDistance(int a, int b){
if(a==b)return 0;
if(a>b)std::swap(a,b);
pii x = {a,b};
if(memoria.find(x)!=memoria.end())return memoria[x];
int d = getDistance(a,b);
memoria[x]=d;
++count;
return d;
}
int dist[MAX][2];
pii MaisDistante(int N,int x,int p){
int best=-1,alvo=0;
for(int i=0;i!=N;++i){
if(i==x)continue;
int d = smartgetDistance(i,x);
if(d>best){
best=d;
alvo=i;
}
dist[i][p]=d;
}
return {best,alvo};
}
int dist_centro[MAX];
///Queries usadas: 3N-3
int hubDistance(int N, int sub) {
count=0;
memoria.clear();
pii alpha = MaisDistante(N,0,1);
pii beta = MaisDistante(N,alpha.second,0);
MaisDistante(N,beta.second,1);
int d = beta.first;
int ans=1e9;
int exp_a=0,exp_b=0;
std::map<pii,bool> hubs;
for(int i=0;i!=N;++i){
if(i==alpha.second||i==beta.second)continue;
int a = dist[i][0];
int b = dist[i][1];
int soma = a+b;
int subt = soma-d;
int base = subt/2;
int custo = std::max(a,b)-base;
exp_a = a-base;
exp_b = b-base;
if(custo<ans){///Fora da sub de A ou B
ans=custo;
hubs.clear();
hubs[{exp_a,exp_b}]=true;
}else if(custo==ans)hubs[{exp_a,exp_b}]=true;
dist_centro[i]=base;
}
if(sub<=2)return ans;
for(auto&z:hubs){
exp_a = z.first.first;
exp_b = z.first.second;
{
int a = dist[z][0];
int b = dist[z][1];
int soma = a+b;
int subt = soma-d;
int base = subt/2;
int custo = std::max(a,b)-base;
exp_a = a-base;
exp_b = b-base;
}
std::vector<int> fora;
int grupos[2]={1,1};
for(int i=0;i!=N;++i){
if(i==alpha.second||i==beta.second)continue;
int a = dist[i][0];
int b = dist[i][1];
int soma = a+b;
int subt = soma-d;
int base = subt/2;
int dist_a = a-base;
int dist_b = b-base;
if(dist_a == exp_a && dist_b == exp_b){///Fora da sub de A ou B
fora.push_back(i);
}else {///Na subarvore de A ou B
if(a>b)grupos[0]++;else grupos[1]++;
}
}
int lim=N/2;
if(grupos[0]>lim||grupos[1]>lim)goto fail;
///Para a sub 4
if(sub==4){
int sum = N-(grupos[0]+grupos[1]);
if(sum>lim)goto fail;
return ans;
}
///Achei o erro:
///Pode ter mais de um hub
///E ele quer saber se qq um deles eh balanceado
assert(fora.size()==(N-(grupos[0]+grupos[1])));
{std::vector<pii> opcoes;
for(auto x:fora){
bool ok=false;
for(int i=0;i!=opcoes.size();++i){
int p = opcoes[i].first;
if(smartgetDistance(p,x)<(dist_centro[x]+dist_centro[p])){
++opcoes[i].second;
if(opcoes[i].second>lim)goto fail;
goto safe;
}
}
if(!ok)
opcoes.push_back({x,1});
safe:{}
}
return ans;}
fail:{}
}
return -ans;
}