//#include<i_am_noob_orz>
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
//#define int ll
#define ull unsigned long long
#define pii pair<int,int>
#define X first
#define Y second
#define mod ((ll)1e9+7)
#define pb push_back
#define mp make_pair
#define abs(x) ((x)>0?(x):(-(x)))
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define memres(a) memset(a,0,sizeof(a))
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())
#define ceiling(a,b) (((a)+(b)-1)/(b))
#define endl '\n'
#define bit_count(x) __builtin_popcountll((x))
#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define jimmy_is_kind false
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> rbtree;
//#define LOCAL
#ifdef LOCAL
#define bug(...) cerr<<"#"<<__LINE__<<' '<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr<<x<<", "; _do(y...);}
#define IOS()
int Query(int x,int y,int z){return x;}
void Bridge(int u,int v){cout<<u<<" "<<v<<endl;}
#else
#include<meetings.h>
#define IOS() ios_base::sync_with_stdio(0), cin.tie(0)
#define endl '\n'
#define bug(...)
#endif
int add(int a,int b){return(a+b>=mod?a+b-mod:a+b);}
int sub(int a,int b){return(a<b?a+mod-b:a-b);}
int po(int a,int b){
if(b==0)return 1;
if(b==1)return(a%mod);
int tem=po(a,b/2);
if(b&1)return(((tem*tem)%mod)*a)%mod;
else return(tem*tem)%mod;
}
int GCD(int a,int b){
int x=0;
int ra,rb;
while(a&&b){
if(((a&1)==0)&&((b&1)==0)){
a>>=1,b>>=1,x++;
}
else if((a^b)&1){
if(a&1)b>>=1;
else a>>=1;
}
else{
ra=abs(a-b),rb=min(a,b);
a=ra,b=rb;
}
}
return max(a,b)<<x;
}
int gcd(int a,int b){if(b==0)return a;return gcd(b,a%b);}
set<int> g[2005];
bool used[2005],vis[2005];
int pa[2005];
pii dfs(int v,int f){
pa[v]=f;
int re0=v,re1=0;
for(int u:g[v]){
if(u==f||vis[u])continue;
pii re=dfs(u,v);
if(re.Y>re1)re0=re.X,re1=re.Y;
}
return {re0,re1+1};
}
void Solve(int n){
int x=Query(0,1,2);
if(x>=0&&x<=2){
F(3){
if(i==x)continue;
g[i].insert(x);
g[x].insert(i);
}
}
else{
F(3){
g[i].insert(x);
g[x].insert(i);
}
}
memres(used);
F(3)used[i]=1;
used[x]=1;
Fl(i,3,n){
if(used[i])continue;
memres(vis);
pii tmp=dfs(0,-1);
int p1=tmp.X;
tmp=dfs(p1,-1);
int p2=tmp.X;
int re;
if(p1!=p2)re=Query(p1,p2,i);
else re=p1;
while(1){
if(re==p1||re==p2){
used[i]=1;
g[re].insert(i);
g[i].insert(re);
break;
}
if(used[re]){
int tp2=p2;
while(tp2!=-1){
vis[tp2]=1;
tp2=pa[tp2];
}
vis[re]=0;
tmp=dfs(re,-1);
p1=tmp.X;
tmp=dfs(p1,-1);
p2=tmp.X;
if(p1!=p2)re=Query(p1,p2,i);
else re=p1;
}
else{
int tp2=p2;
vector<int> v;
while(tp2!=-1){
v.pb(tp2);
tp2=pa[tp2];
}
int l=0,r=sz(v)-1;
while(l+1<r){
int mi=(l+r)/2;
int t1=Query(v[l],v[mi],i);
if(t1!=v[mi])r=mi;
else l=mi;
}
assert(l+1==r);
p1=v[l],p2=v[r];
g[p1].erase(g[p1].find(p2));
g[p2].erase(g[p2].find(p1));
g[p1].insert(re);
g[re].insert(p1);
g[p2].insert(re);
g[re].insert(p2);
g[re].insert(i);
g[i].insert(re);
used[i]=1;
used[re]=1;
break;
}
}
}
F(n){
for(int j:g[i]){
if(i<j)Bridge(i,j);
}
}
}
#ifdef LOCAL
signed main(){
int n;
cin>>n;
Solve(n);
return 0;
}
#endif
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
328 KB |
Output is correct |
| 2 |
Correct |
1 ms |
328 KB |
Output is correct |
| 3 |
Correct |
1 ms |
328 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
328 KB |
Wrong Answer [4] |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
328 KB |
Output is correct |
| 2 |
Correct |
1 ms |
328 KB |
Output is correct |
| 3 |
Correct |
1 ms |
328 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
328 KB |
Wrong Answer [4] |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
328 KB |
Output is correct |
| 2 |
Correct |
1 ms |
328 KB |
Output is correct |
| 3 |
Correct |
1 ms |
328 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
328 KB |
Wrong Answer [4] |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
119 ms |
1052 KB |
Wrong Answer [4] |
| 2 |
Halted |
0 ms |
0 KB |
- |
