| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 865978 | yeediot | Race (IOI11_race) | 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>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
//Don't open the standings during contests.
const int mxn=2e5+5;
vector<pii>adj[mxn];
int cnt[mxn];
bool vis[mxn];
void cnt_sz(int v,int pa){
cnt[v]=1;
for(auto [u,d]:adj[v]){
if(vis[u] or u==pa)continue;
cnt_sz(u,v);
cnt[v]+=cnt[u];
}
}
int find(int v,int pa,int tar){
for(auto [u,d]:adj[v]){
if(vis[u] or u==pa)continue;
if(cnt[u]*2>tar)return find(u,v,tar);
}
return v;
}
int ans=8e10;
vector<pii>dis;
void dfs(int v,int pa,int l,int len,int k){
//cout<<v<<' '<<l<<' '<<len<<'\n';
if(l>k)return;
dis.pb({l,len});
for(auto [u,d]:adj[v]){
if(vis[u] or u==pa)continue;
dfs(u,v,l+1,len+d,k);
}
}
int f[mxn];
void cd(int v,int k,int n){
cnt_sz(v,v);
v=find(v,v,cnt[v]);
vis[v]=1;
vector<int>undo;
for(auto [u,d]:adj[v]){
if(vis[u])continue;
dis.clear();
dis.pb({0,0});
dfs(u,v,1,d,k);
for(int j=0;j<sz(dis);j++){
chmin(ans,f[k-dis[j].S]+dis[j].F);
// cout<<u<<' '<<dis[j].S<<' '<<dis[j].F<<' '<<f[k-dis[j].S]<<' '<<ans<<'\n';
}
for(int j=0;j<sz(dis);j++){
undo.pb(dis[j].S);
chmin(f[dis[j].S],dis[j].F);
}
}
for(auto x:undo)f[x]=8e10;
for(auto [u,d]:adj[v]){
if(vis[u])continue;
cd(u,k,n);
}
}
int best_path(int N,int K,int H[][2],int L[]){
for(int i=0;i<N-1;i++){
adj[H[i][0]].pb({H[i][1],L[i]});
adj[H[i][1]].pb({H[i][0],L[i]});
}
for(int i=0;i<=K;i++){
f[i]=8e10;
}
cd(0,K,N);
return (ans==8e10?-1:ans);
}
/*signed main(){
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int n,k;
cin>>n>>k;
int h[n-1][2];
int l[n-1];
for(int i=0;i<n-1;i++){
cin>>h[i][0]>>h[i][1];
}
for(int i=0;i<n-1;i++){
cin>>l[i];
}
cout<<best_path(n,k,h,l);
}*/
/*
input:
11 12
0 1
0 2
2 3
3 4
4 5
0 6
6 7
6 8
8 9
8 10
3
4
5
4
6
3
2
5
6
7
*/