Submission #1150988

#	Time	Username	Problem	Language	Result	Execution time	Memory
1150988		Shadow1	Race (IOI11_race)	C++20	0 / 100	8 ms	15936 KiB

race

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

using ll = long long;

#define pii pair<int,int>
#define fir first
#define sec second
#define sz(x) ll(x.size())
// #define int long long


const int maxn = 2e5 + 5;
unordered_map<int, int> mp[maxn];  // mp[u][x] is length of minimum path with u as root and sum = x. (sum, min edges)
vector<pii> adj[maxn];

void dfs(int u, int p) {
  for(auto &k : adj[u]) {
      int w = k.sec, v = k.fir;
      if(v == p) continue;
      dfs(v, u);
      mp[u][w] = 1;
      if(sz(mp[u]) < sz(mp[v])) swap(mp[u], mp[v]);
      for(auto &x : mp[v]) {
          if(mp[u][x.fir] > 0)
              mp[u][x.fir] = min(mp[u][x.fir], x.sec);
          else
              mp[u][x.fir] = x.sec;
          if(mp[u][w+x.fir] > 0)
              mp[u][w+x.fir] = min(mp[u][w+x.fir], x.sec + 1);
          else
              mp[u][w+x.fir] = x.sec + 1;
      }
  }
}

int best_path(int N, int K, int H[][2], int L[])
{
  int n = N, k = K;
  for(int i=0; i<n; ++i) {
    adj[H[i][0]].push_back({H[i][1], L[i]});
    adj[H[i][1]].push_back({H[i][0], L[i]});
  }
  dfs(0, -1);
  int ans = maxn;
  for(int i=0; i<n; ++i) {
    if(mp[i][k] > 0)
        ans = min(ans, mp[i][k]);
  }
  return (ans == maxn ? -1 : ans);
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57