# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1111943 | epicci23 | Highway Tolls (IOI18_highway) | 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"
#include "highway.h"
#define all(v) v.begin() , v.end()
#define sz(a) (int)a.size()
using namespace std;
const int N = 1e5 + 5;
vector<int> v[N],Xor,depth[N],Res;
int n,m,A,B,Dist,vis[N],par[N],sub[N];
inline int oth(int c,int u) {return Xor[c] ^ u;}
void upd(int c,int d){
sub[c]=1;
depth[d].push_back(c);
for(int ind:v[c]){
int x = oth(ind,c);
if(ind==par[c] || vis[x]) continue;
par[x]=ind;
upd(x,d+1);
sub[c]+=sub[x];
}
}
int we_know_root(int rt){
for(int i=0;i<N;i++) depth[i].clear();
par[rt]=-1;
upd(rt,rt,0);
int l = 0 , r = sz(depth[Dist]) - 1;
while(l<r){
int mid = (l+r)/2;
Res.assign(m,0);
for(int i=0;i<=mid;i++){
int cur = depth[Dist][i];
while(cur != rt){
Res[par[cur]]=1;
cur = oth(par[cur], cur);
}
}
if(ask(Res)==Dist*B) r=mid;
else l=mid+1;
}
return depth[Dist][l];
}
void find_pair(int _n, vector<int> U, vector<int> V, int _A, int _B){
A=_A,B=_B;
m = sz(U),n = _n;
for(int i=0;i<m;i++){
Xor.push_back(U[i]^V[i]);
v[U[i]].push_back(i);
v[V[i]].push_back(i);
}
Res.assign(m,0);
Dist = ask(Res) / A;
answer(0, we_know_root(0));
}