Submission #933508

#	Time	Username	Problem	Language	Result	Execution time	Memory
933508		Maaxle	Race (IOI11_race)	C++17	0 / 100	1 ms	2392 KiB

race

#include "race.h"
#include <bits/stdc++.h>

#define range(it, a, b) for (ll it = a; it < b; it++)
#define all(x) begin(x), end(x)
#define ll long long
#define ull unsigned long long
#define INF64 ((ll) 1 << 60)
#define INF32 (1 << 30)
#define mset multiset
#define uset unordered_set
#define umap unordered_map 
#define pqueue priority_queue
#define ptr(A) shared_ptr<A>

using namespace std;

struct Path {
  ll i, w;
};

ll n, k;
vector<vector<Path>> adj;

// DISTANCE, NO. OF ROADS
vector<map<ll, ll>> paths;
ll ans = INF64;

void explore(ll i, ll from) {
  paths[i][0] = 0;

  for (Path child : adj[i]) {    
    if (child.i != from) {
      explore(child.i, i);

      if (paths[i].size() < paths[child.i].size())
        swap(paths[child.i], paths[i]);

      for (auto child_path : paths[child.i]) {
        ll dist = child.w + child_path.first;
        if (paths[i].count(k - dist))
          ans = min(ans, paths[i][k - dist] + 1 + child_path.second);
      }

      for (auto child_path : paths[child.i]) {
        ll dist = child.w + child_path.first;
        if (!paths[i].count(dist))
          paths[i][dist] = 1 + child_path.second;
        else 
          paths[i][dist] = min(paths[i][dist], 1 + child_path.second);
      }
    }
  }
}

int best_path(int N, int K, int H[][2], int L[]) {
  n = N; k = K;
  adj.resize(n);
  paths.resize(n);

  range(i, 0, n) {
    adj[H[i][0]].push_back({H[i][1], L[i]});
    adj[H[i][1]].push_back({H[i][0], L[i]});
  }

  explore(0, 0);
  return (ans == INF64 ? -1 : ans);
}

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