# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
833816 | MODDI | Race (IOI11_race) | 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 <bits/stdc++.h>
#include "race.h"
#include "grader.cpp"
using namespace std;
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef pair<long long, long long> pll;
typedef pair<int,int> pii;
typedef vector<long long> vl;
typedef vector<int> vi;
vector<pii> G[200100];
vi sz, vis;
map<int, int> mapa;
int ans = 1e8, req_len;
int dfs_sz(int node, int p){
sz[node] = 1;
for(auto next : G[node]){
if(next.first != p && !vis[next.first]){
sz[node] += dfs_sz(next.first, node);
}
}
return sz[node];
}
int find_centroid(int node, int p, int n){
for(auto next : G[node]){
if(next.first != p && !vis[next.first] && sz[next.first] * 2 >= n)
return find_centroid(next.first, node, n);
}
return node;
}
void proveri(int node, int p, int dist, int cnt){
if(dist > req_len) return;
if(req_len - dist == 0){
ans = min(ans, cnt);
}
else if(req_len - dist != 0 && mapa[req_len - dist] != 0){
ans = min(ans, mapa[req_len - dist] + cnt);
}
for(auto next : G[node]){
if(next.first != p && !vis[next.first])
proveri(next.first, node, dist + next.second, cnt + 1);
}
}
void dodadi(int node, int p, int dist, int cnt){
if(dist > req_len) return ;
if(mapa[dist] == 0) mapa[dist] = cnt;
else
mapa[dist] = min(mapa[dist], cnt);
for(auto next : G[node]){
if(next.first != p && !vis[next.first])
dodadi(next.first, node, dist + next.second, cnt + 1);
}
}
void recur(int node, int p){
int n = dfs_sz(node, p);
int centroid = find_centroid(node, p, n);
vis[centroid] = true;
mapa = map<int,int>();
for(auto next : G[centroid]){
if(!vis[next.first]){
proveri(next.first, centroid, next.second, 1);
dodadi(next.first, centroid, next.second, 1);
}
}
for(auto next : G[centroid]){
if(next.first != p && !vis[next.first]){
recur(next.first, centroid);
}
}
}
int best_path(int N, int K, int H[][2], int L[]){
req_len = K;
sz = vi(N);
vis = vi(N, false);
for(int i = 0; i < N-1; i++){
G[H[i][0]].pb(mp(H[i][1], L[i]));
G[H[i][1]].pb(mp(H[i][0], L[i]));
}
recur(0, 0);
if(ans >= 1e9) return -1;
return ans;
}