# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
419142 | NintsiChkhaidze | Stations (IOI20_stations) | 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 "stations.h"
#nclude <bits/stdc++.h>
//#include <iostream>
//#include <vector>
#define pb push_back
using namespace std;
vector <int> vec[1005];
int dp[1005],d[23][1005];
void dfs(int x,int p){
d[0][x] = p;
dp[x] = dp[p] + 1;
for (int j=0;j<vec[x].size();j++){
int to = vec[x][j];
if (to == p) continue;
dfs(to,x);
}
}
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
vector<int> labels;
for (int i=0;i<1001;i++){
vec[i].clear();
dp[i] = 0;
}
for (int i=0;i<u.size();i++){
vec[u[i]].pb(v[i]);
vec[v[i]].pb(u[i]);
}
dfs(0,0);
for (int i=0;i<n;i++)
for (int j = 1; j <= 18; j++)
d[j][i] = d[j - 1][d[j - 1][i]];
for (int i=0;i<n;i++)
labels.pb(i);
return labels;
}
int lca(int x,int y){
for (int j = 18; j>= 0;j--)
if (dp[d[j][x]] >= dp[y]) x = d[j][x];
if (x == y) return x;
for (int j = 18; j>=0;j--)
if (d[j][x] != d[j][y]) x = d[j][x],y = d[j][y];
return d[0][x];
}
int dis(int x,int y){
if (dp[x] < dp[y]) swap(x,y);
int c = lca(x,y);
//cout<<x<<" ^^ "<<y<<" lca = "<<c<<endl;
return dp[x] +dp[y] - 2*dp[c];
}
int find_next_station(int s, int t, vector<int> c) {
int D = dis(s,t),ans=-1;
for (int i=0;i<c.size();i++){
int DD = dis(c[i],t);
// cout<<"DD == "<<DD<<" "<<c[i]<<" ^ "<<t<<endl;
if (DD < D) ans = c[i];
}
//cout<<"ans = "<<ans<<endl;
return ans;
}