#include "highway.h"
#include <bits/stdc++.h>
//#include "grader.cpp"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
mt19937 rng(chrono::steady_clock().now().time_since_epoch().count());
int n,m,niv[100005],par[100005],topar[100005],dp[21][100005],in[100005],out[100005],timp;
ll dist,AA,BB;
vector<pii> muchii[100005];
vector<pii> g;
vector<int> w;
ll memo[100005],calls;
bool isancestor(int a,int b)
{
return in[a]<=in[b]&&out[a]>=out[b];
}
int LCA(int a,int b)
{
if(niv[a]>niv[b])
swap(a,b);
if(isancestor(a,b))
return a;
for(int i=20;i>=0;i--)
if(dp[i][a]!=-1&&!isancestor(dp[i][a],b))
a=dp[i][a];
return par[a];
}
void dfs(int nod)
{
timp++;
in[nod]=timp;
dp[0][nod]=par[nod];
for(int i=1;i<=20;i++)
{
if(dp[i-1][nod]==-1)
{
dp[i][nod]=-1;
continue;
}
dp[i][nod]=dp[i-1][dp[i-1][nod]];
}
for(auto i:muchii[nod])
if(i.first!=par[nod])
{
par[i.first]=nod;
niv[i.first]=niv[nod]+1;
topar[i.first]=i.second;
dfs(i.first);
}
out[nod]=timp;
}
ll buildniv(int p)
{
if(memo[p]!=0)
return memo[p];
for(int i=0;i<m;i++)
{
w[i]=1;
if(min(niv[g[i].first],niv[g[i].second])<=p)
w[i]=0;
}
calls++;
assert(calls<=60);
memo[p]=ask(w);
return memo[p];
}
int getnode(vector<int> cand)
{
while(true)
{
if(cand.size()==1)
return cand[0];
vector<int> x,y;
int lg=cand.size();
for(int i=0;i<cand.size();i++)
{
if(i<lg/2)
x.push_back(cand[i]);
else
y.push_back(cand[i]);
}
for(int i=0;i<m;i++)
w[i]=1;
for(int i:x)
w[topar[i]]=0;
calls++;
assert(calls<=60);
ll val=ask(w);
if(val<dist*BB)
cand=x;
else
cand=y;
}
return -1;
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B)
{
AA=A;
BB=B;
n=N;
m=U.size();
for(int i=0;i<m;i++)
{
int a=U[i],b=V[i];
g.push_back({a,b});
muchii[a].push_back({b,i});
muchii[b].push_back({a,i});
}
for(int i=0;i<n;i++)
par[i]=-1;
int root=rng()%n;
niv[root]=1;
dfs(root);
int nivmax=0;
for(int i=0;i<n;i++)
nivmax=max(nivmax,niv[i]);
for(int i=0;i<m;i++)
w.push_back(0);
calls++;
assert(calls<=60);
dist=ask(w)/A;
int nivlca=nivmax;
int st=1;
int dr=nivmax-1;
while(st<=dr)
{
int mij=(st+dr)/2;
ll val=buildniv(mij);
if(val<dist*B)
{
nivlca=mij;
dr=mij-1;
}
else
st=mij+1;
}
int nivS=nivlca;
int nivT=0;
st=nivlca;
dr=nivmax-1;
while(st<=dr)
{
int mij=(st+dr)/2;
ll nra=2*(mij-nivlca);
if(nra<=dist)
{
ll val=buildniv(mij);
ll val2=buildniv(mij-1);
if(val2==val+2LL*(B-A))
{
nivS=mij+1;
st=mij+1;
continue;
}
}
dr=mij-1;
}
nivT=nivlca+(dist-(nivS-nivlca));
//assert(nivS<=nivT);
vector<int> c1,c2;
for(int i=0;i<n;i++)
{
if(niv[i]==nivS)
c1.push_back(i);
if(niv[i]==nivT)
c2.push_back(i);
}
int T=getnode(c2);
if(nivS!=nivT)
{
c1.clear();
for(int i=0;i<n;i++)
if(niv[i]==nivS&&niv[LCA(i,T)]==nivlca)
c1.push_back(i);
}
int S=getnode(c1);
//assert(S!=T);
//assert(S!=-1&&T!=-1);
answer(S,T);
}
Compilation message
highway.cpp: In function 'int getnode(std::vector<int>)':
highway.cpp:76:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
76 | for(int i=0;i<cand.size();i++)
| ~^~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
13140 KB |
Output is correct |
| 2 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 3 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 4 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 5 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 6 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 7 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 8 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 9 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 10 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 11 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 12 |
Correct |
2 ms |
12632 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
12732 KB |
Output is correct |
| 2 |
Correct |
10 ms |
13652 KB |
Output is correct |
| 3 |
Incorrect |
89 ms |
20288 KB |
Output is incorrect: {s, t} is wrong. |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
10 ms |
14036 KB |
Output is correct |
| 2 |
Correct |
21 ms |
15480 KB |
Output is correct |
| 3 |
Correct |
24 ms |
16632 KB |
Output is correct |
| 4 |
Correct |
79 ms |
23796 KB |
Output is correct |
| 5 |
Correct |
70 ms |
23712 KB |
Output is correct |
| 6 |
Correct |
78 ms |
23032 KB |
Output is correct |
| 7 |
Correct |
71 ms |
24584 KB |
Output is correct |
| 8 |
Correct |
81 ms |
24096 KB |
Output is correct |
| 9 |
Correct |
73 ms |
24532 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
12632 KB |
Output is correct |
| 2 |
Correct |
9 ms |
13580 KB |
Output is correct |
| 3 |
Incorrect |
75 ms |
18876 KB |
Output is incorrect: {s, t} is wrong. |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
800 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
520 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
