제출 #603906

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
603906		erekle	통행료 (IOI18_highway)	C++17	5 / 100	303 ms	262144 KiB

highway

#include "highway.h"
#include <iostream>

using namespace std;

vector<vector<pair<int, int>>> g;
vector<int> parent, edgeUp, depth;

void rootDFS(int node, int d = 0, int eUP = -1, int par = -1) {
  parent[node] = par;
  edgeUp[node] = eUP;
  depth[node] = d;
  for (auto [child, e] : g[node]) {
    if (child != par) rootDFS(child, d+1, e, node);
  }
}
void rootTree(int root, int N) {
  parent.resize(1+N);
  edgeUp.resize(1+N);
  depth.resize(1+N);
  rootDFS(root);
}
vector<int> nodesDepth(int d) {
  vector<int> v;
  for (int i = 0; i < (int)depth.size(); ++i) {
    if (depth[i] == d) v.push_back(i);
  }
  return v;
}

void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
  g.resize(1+N);
  int M = U.size();
  for (int i = 0; i < M; ++i) {
    g[U[i]].emplace_back(V[i], i);
    g[V[i]].emplace_back(U[i], i);
  }
  vector<int> w(M);
  long long toll = ask(w);

  // Solve for tree, one end is known
  int S = 0;
  rootTree(S, N);
  vector<int> candidates = nodesDepth(toll/A);
  int l = 0, r = (int)candidates.size(); // in range [l, r)
  while (l+1 < r) {
    int mid = (l+r)/2;
    for (int i = mid; i < r; ++i) w[edgeUp[candidates[i]]] = 1;
    int res = ask(w);
    for (int i = mid; i < r; ++i) w[edgeUp[candidates[i]]] = 0;
    if (res == toll) r = mid;
    else l = mid;
  }
  int T = candidates[l];
  answer(S, T);
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31