Submission #423607

#	Time	Username	Problem	Language	Result	Execution time	Memory
423607		Tangent	Highway Tolls (IOI18_highway)	C++17	12 / 100	181 ms	9608 KiB

highway

#include "highway.h"
#include "bits/stdc++.h"

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vii;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<vii> vvii;
typedef vector<vll> vvll;
typedef vector<vpii> vvpii;
typedef vector<vpll> vvpll;

#define ffor(i, a, b) for (ll i = a; i < b; i++)
#define rep(i, n) ffor(i, 0, n)
#define forin(x, a) for (auto &x: a)
#define all(a) a.begin(), a.end()

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
  int M = U.size();
  vvpii adj(N);
  rep(i, M) {
    adj[U[i]].emplace_back(V[i], i);
    adj[V[i]].emplace_back(U[i], i);
  }

  vii depth(N, -1), pedge(N, -1);
  depth[0] = 0;

  function<void(int)> dfs;
  dfs = [&](int x) {
    forin(y, adj[x]) {
      if (depth[y.first] == -1) {
        depth[y.first] = depth[x] + 1;
        pedge[y.first] = y.second;
        dfs(y.first);
      }
    }
  };
  dfs(0);

  ll tdepth = ask(vii(M)) / A;
  vii cand;
  rep(i, N) {
    if (depth[i] == tdepth) {
      cand.emplace_back(i);
    }
  }
  while (cand.size() > 1) {
    vii query(M);
    rep(i, cand.size() / 2) {
      query[pedge[cand[i]]] = 1;
    }
    if (ask(query) > tdepth * A) {
      cand.resize(cand.size() / 2);
    } else {
      ffor(i, cand.size() / 2, cand.size()) {
        cand[i - (cand.size() / 2)] = cand[i]; 
      }
      cand.resize(cand.size() - (cand.size() / 2));
    }
  }

  answer(0, cand[0]);
}

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:18:40: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 | #define ffor(i, a, b) for (ll i = a; i < b; i++)
      |                                        ^
highway.cpp:19:19: note: in expansion of macro 'ffor'
   19 | #define rep(i, n) ffor(i, 0, n)
      |                   ^~~~
highway.cpp:55:5: note: in expansion of macro 'rep'
   55 |     rep(i, cand.size() / 2) {
      |     ^~~
highway.cpp:18:40: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 | #define ffor(i, a, b) for (ll i = a; i < b; i++)
......
   61 |       ffor(i, cand.size() / 2, cand.size()) {
      |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
highway.cpp:61:7: note: in expansion of macro 'ffor'
   61 |       ffor(i, cand.size() / 2, cand.size()) {
      |       ^~~~

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