| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1098387 | MMihalev | Highway Tolls (IOI18_highway) | C++14 | 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 "highway.h"
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
const int MAX_N=1e5+5;
int n,m;
vector<int>w;
vector<pair<int,int> >g[MAX_N];
long long edges,cost;
int root;
int a,b;
int parent[MAX_N];
int paredge[MAX_N];
int depth[MAX_N];
vector<int>leaves;
vector<int>ends;
void initdfs(int u,int par)
{
parent[u]=par;
for(auto [v,edge] : g[u])
{
if(v==par)continue;
depth[v]=depth[u]+1;
paredge[v]=edge;
initdfs(v,u);
}
}
int onpath(int l,int r)
{
if(l==r)return l;
int mid=(l+r)/2;
for(int u=l;u<=mid;u++)
{
for(auto [v,edge]:g[u])
{
w[edge]=1;
}
}
long long ncost=ask(w);
for(int u=l;u<=mid;u++)
{
for(auto [v,edge]:g[u])
{
w[edge]=0;
}
}
if(ncost>cost)
{
return onpath(l,mid);
}
return onpath(mid+1,r);
}
void markdfs(int u,bool f)
{
w[paredge[u]]=f;
for(auto [v,edge]:g[u])
{
if(v==parent[u])continue;
markdfs(v,f);
}
}
void leavesdfs(int u)
{
for(auto [v,edge]:g[u])
{
if(v==parent[u])continue;
leavesdfs(v);
}
if(u!=root g[u].size()==1)leaves.push_back(u);
}
void goup(int u,bool f)
{
if(u==root)return;
w[paredge[u]]=f;
goup(parent[u],f);
}
int rec(int l,int r,int cnt)
{
if(l==r)
{
int u=leaves[l];
int ups=depth[u]-cnt;
while(ups--)
{
u=parent[u];
}
return u;
}
int mid=(l+r)/2;
for(int i=l;i<=mid;i++)
{
goup(leaves[i],1);
}
long long ncost=ask(w);
for(int i=l;i<=mid;i++)
{
goup(leaves[i],0);
}
if((ncost-cost)/b==edges)return rec(l,mid,cnt);
return rec(mid+1,r,cnt);
}
void solve(int l,int r,int cnt)
{
leaves.clear();
for(int i=l;i<=r;i++)
{
leavesdfs(g[root][i].first);
}
ends.push_back(rec(0,leaves.size()-1,cnt));
}
void solvetwo(int l,int r)
{
int mid=(l+r)/2;
for(int i=l;i<=mid;i++)
{
markdfs(g[root][i].first,1);
}
long long ncost=ask(w);
for(int i=l;i<=mid;i++)
{
markdfs(g[root][i].first,1);
}
if((ncost-cost)/b==0)solvetwo(mid+1,r);
else if((ncost-cost)/b==edges)solvetwo(l,mid);
else
{
int edges1=(ncost-cost)/b;
solve(l,mid,edges1);
solve(mid+1,r,edges-edges1);
}
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B)
{
n=N;
m=U.size();
w.resize(m);
a=A;
b=B;
for(int i=0;i<m;i++)
{
g[U[i]].push_back({V[i],i});
g[V[i]].push_back({U[i],i});
}
cost=ask(w);
edges=cost/A;
root=onpath(0,n-1);
initdfs(root,-1);
bool twodifferent=0;
for(int i=0;i<g[root].size();i++)
{
w[g[root][i].second]=1;
}
long long ncost=ask(w);
if((ncost-cost)/b==2)twodifferent=1;
for(int i=0;i<g[root].size();i++)
{
w[g[root][i].second]=1;
}
if(!twodifferent)
{
ends.push_back(root);
solve(0,g[root].size()-1,edges);
}
else
{
solvetwo(0,g[root].size()-1);
}
answer(ends[0],ends[1]);
}