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>
//#include "books.h"
using namespace std;
//#include "simurgh.h"
int count_common_roads(const std::vector<int>& r);
#define MAX 512*512
const int white=MAX-3;
const int black=MAX-2;
int dd[601][601];
struct UF{
int belong[MAX];
int sz[MAX];
int col[MAX];
UF(){
memset(belong,-1,sizeof(belong));
for(int i=0;i<MAX;i++)sz[i]=1;
}
inline int root(int b){
if(belong[b]==-1){
return b;
}
return belong[b]=root(belong[b]);
}
void merge(int a,int b){
int ta=a;
int tb=b;
a=root(a);
b=root(b);
if(a==b)return;
if(a>b)swap(a,b);
belong[a]=b;
sz[b]+=sz[a];
}
};
UF uf;
struct UFb{
int belong[MAX];
int sz[MAX];
int col[MAX];
vector<int> z[MAX];
UFb(){
memset(belong,-1,sizeof(belong));
for(int i=0;i<MAX;i++)sz[i]=1;
}
inline int root(int b){
if(belong[b]==-1){
return b;
}
return belong[b]=root(belong[b]);
}
void merge(int a,int b){
int ta=a;
int tb=b;
a=root(a);
b=root(b);
if(a==b)return;
if(root(black)==a||root(black)==b){
for(int el1:z[a]){
if(el1>=600)continue;
for(int el2:z[b]){
if(el2>=600)continue;
if(ta==el1&&tb==el2)continue;
if(dd[el1][el2]==-1)continue;
uf.merge(white,dd[el1][el2]);
}
}
}
if(a>b)swap(a,b);
belong[a]=b;
for(int el:z[a]){
z[b].push_back(el);
}
z[a].clear();
sz[b]+=sz[a];
}
};
namespace solver{
vector<pair<int,int> > v;
vector<pair<int,int> > g[MAX];
int id[MAX];
int pr[MAX];
int dep[MAX];
vector<int> road;
vector<int> swa;
UFb bl;
inline void dfs(int b,int pr2=-1,int d=0){
dep[b]=d;
for(auto go:g[b]){
if(go.first==pr2)continue;
dfs(go.first,b,d+1);
pr[go.first]=b;
id[go.first]=go.second;
}
}
int ini;
int cn;
int ask(){
cn++;
if(cn>30000-2){
while(1);
}
return count_common_roads(road);
}
void make_tree(){
UF uf2;
for(int i=0;i<v.size();i++){
swa.push_back(-1);
if(uf2.root(v[i].first)!=uf2.root(v[i].second)){
uf2.merge(v[i].first,v[i].second);
g[v[i].first].push_back(make_pair(v[i].second,i) );
g[v[i].second].push_back(make_pair(v[i].first,i) );
road.push_back(i);
swa[i]=road.size()-1;
}
}
ini=ask();
}
int query(int exp,int add){
road[swa[exp]]=add;
int z=ask();
road[swa[exp]]=exp;
return z-ini;
}
inline void check(int tree1,int tree2){
int r1=uf.root(tree1);
int r2=uf.root(tree2);
if(r1==r2)return;
if(r1==black||r1==white){
if(r2==black||r2==white){
return;
}
}
int ret=query(tree1,tree2);
if(ret==0){
if(r1==black||r2==black){
bl.merge(v[tree2].first,v[tree2].second);
bl.merge(v[tree1].first,v[tree1].second);
}
uf.merge(tree1,tree2);
return;
}
if(ret>0){
bl.merge(v[tree2].first,v[tree2].second);
uf.merge(black,tree2);
uf.merge(white,tree1);
return;
}
bl.merge(v[tree1].first,v[tree1].second);
uf.merge(black,tree1);
uf.merge(white,tree2);
}
vector<int> mer[MAX];
std::vector<int> find_roads(int n, std::vector<int> u1, std::vector<int> v1) {
memset(dd,-1,sizeof(dd));
for(int i=0;i<u1.size();i++){
v.push_back(make_pair(u1[i],v1[i]));
dd[u1[i]][v1[i]]=i;
dd[v1[i]][u1[i]]=i;
}
for(int i=0;i<MAX;i++){
bl.z[i].push_back(i);
}
make_tree();
if(ini==n-1){
return road;
}
if(ini==0){
for(int i=0;i<road.size();i++){
uf.merge(road[i],white);
}
}
dfs(0);
for(int i=0;i<v.size();i++){
if(dep[v[i].first]>dep[v[i].second])swap(v[i].first,v[i].second);
if(pr[v[i].second]==v[i].first)continue;
int a=v[i].first;
int b=v[i].second;
while(a!=b){
if(dep[a]<dep[b]){
check(id[b],i);
b=pr[b];
}
else{
check(id[a],i);
a=pr[a];
}
}
}
vector<int> ans;
UF uf2;
for(int i=0;i<v.size();i++){
if(uf.root(i)==black){
ans.push_back(i);
uf2.merge(v[i].first,v[i].second);
}
}
for(int i=0;i<v.size();i++){
mer[uf.root(i)].push_back(i);
}
/*for(int i=0;i<v.size();i++){
if(i==white||i==black)continue;
//mergeable
if(mer[i].size()==0)continue;
UF uf3;
bool ok=false;
for(int el:mer[i]){
int a=v[el].first;
int b=v[el].second;
if(uf3.root(a)==uf3.root(b)){
ok=true;
break;
}
uf3.merge(a,b);
if(uf2.root(a)==uf2.root(b)){
ok=true;
break;
}
}
if(ok==false){
for(int el:mer[i]){
road.push_back(el);
int a=v[el].first;
int b=v[el].second;
//uf2.merge(a,b);
}
}
}*/
//assert(ans.size()>=n-1);
if(bl.sz[bl.root(0)]!=n)while(1);
return ans;
}
}
std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v) {
return solver::find_roads(n,u,v);
}
Compilation message (stderr)
simurgh.cpp: In member function 'void UF::merge(int, int)':
simurgh.cpp:28:7: warning: unused variable 'ta' [-Wunused-variable]
int ta=a;
^~
simurgh.cpp:29:7: warning: unused variable 'tb' [-Wunused-variable]
int tb=b;
^~
simurgh.cpp: In function 'void solver::make_tree()':
simurgh.cpp:109:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<v.size();i++){
~^~~~~~~~~
simurgh.cpp: In function 'std::vector<int> solver::find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:158:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<u1.size();i++){
~^~~~~~~~~~
simurgh.cpp:171:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<road.size();i++){
~^~~~~~~~~~~~
simurgh.cpp:176:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<v.size();i++){
~^~~~~~~~~
simurgh.cpp:194:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<v.size();i++){
~^~~~~~~~~
simurgh.cpp:200:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<v.size();i++){
~^~~~~~~~~
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