제출 #1272142

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1272142		efeg	경주 (Race) (IOI11_race)	C++20	100 / 100	323 ms	110872 KiB

race

#include <bits/stdc++.h>
using namespace std;
#include "race.h"

#define int long long 
#define pb push_back
#define F first
#define S second

const int maxN = 2e5 + 100; 

typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;  

vector<vii> adj; 
vi dist,depth; 
set<ii> st[maxN]; 
int n,k,ans = maxN; 

void calDist(int node,int p){
  for (auto tp : adj[node]){
    int to,w; tie(to,w) = tp;
    if (to == p) continue;
    dist[to] = dist[node] + w;
    depth[to] = depth[node] + 1; 
    calDist(to,node); 
  }
}

void dfs(int node,int p){
  st[node].insert({dist[node],depth[node]}); 
    
  for (auto tp : adj[node]){
    int to,w; tie(to,w) = tp;
    if (to == p) continue;
    dfs(to,node); 
    if (st[node].size() < st[to].size()) swap(st[node],st[to]);
    
    for (auto x : st[to]){
      int tmp = k + 2 * dist[node] - x.F;  
      auto itr = st[node].lower_bound({tmp,-maxN});
      if (itr == st[node].end() || itr->F != tmp) continue;
      else {
        ans = min(ans,x.S + itr->S - 2 * depth[node]); 
      } 
    }
    for (auto x : st[to]){
      st[node].insert(x); 
    }
  }
}


int32_t best_path(int32_t N, int32_t K, int32_t H[][2], int32_t L[])
{
  n = N; k = K; 
  adj.assign(n+10,vii()); 
  dist.assign(n+10,0); 
  depth.assign(n+10,0); 
  for (int i = 0; i < n-1; i++){
    int u = H[i][0], v = H[i][1], w = L[i]; 
    adj[u].emplace_back(v,w);
    adj[v].emplace_back(u,w);
  }
  depth[0] = 0; 
  dist[0] = 0;
  calDist(0,-1);
  dfs(0,-1);  

  return (ans == maxN ? -1 : ans); 
}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57