Submission #1001337

# Submission time Handle Problem Language Result Execution time Memory
1001337 2024-06-18T21:39:38 Z spacewalker Longest Trip (IOI23_longesttrip) C++17
0 / 100
9 ms 436 KB
#include <bits/stdc++.h>
#include "longesttrip.h"

using namespace std;

optional<int> find_edge_between(vector<int> s, int v) {
  if (!are_connected(s, {v})) return nullopt;
  vector<int> current = s;
  while (current.size() > 1) {
    int hs = current.size() / 2;
    vector<int> h1(begin(current), begin(current) + hs), h2(begin(current) + hs, end(current));
    if (are_connected(h1, {v})) current = h1;
    else current = h2;
  }
  return current[0];
}

optional<pair<int, int>> find_edge_between(vector<int> s1, vector<int> s2) {
  if (!are_connected(s1, s2)) return nullopt;
  vector<int> current = s1;
  while (current.size() > 1) {
    int hs = current.size() / 2;
    vector<int> h1(begin(current), begin(current) + hs), h2(begin(current) + hs, end(current));
    if (are_connected(h1, s2)) current = h1;
    else current = h2;
  }
  return make_pair(current[0], find_edge_between(s2, current[0]).value());
}

std::vector<int> longest_trip(int N, int D) {
  deque<int> p1{0}, p2;
  for (int i = 1; i < N; ++i) {
    if (are_connected({p1.back()}, {i})) {
      if (are_connected({i}, {p2.front()})) {
        p1.push_back(i);
        p1.insert(end(p1), begin(p2), end(p2));
        p2.clear();
      } else {
        p1.push_back(i);
      }
    } else if (!p2.empty()) {
      p2.push_front(i);
    } else {
      p2.push_back(i);
    }
  }
  /*
  cout << "p1: ";
  for (int v : p1) cout << v;
  cout << endl;
  cout << "p2: ";
  for (int v : p2) cout << v;
  cout << endl;
  */
  vector<int> fp1(p1.begin(), p1.end()), fp2(p2.begin(), p2.end());
  if (fp1.size() == N) return fp1;
  if (fp2.size() > 1 && !are_connected({fp2.front()}, {fp2.back()})) {
    vector<int> ans = fp1;
    reverse(begin(fp2), end(fp2));
    ans.insert(end(ans), begin(fp2), end(fp2));
    return ans;
  }
  if (fp1.size() > 1 && !are_connected({fp1.front()}, {fp1.back()})) {
    vector<int> ans = fp2;
    reverse(begin(fp2), end(fp2));
    ans.insert(end(ans), begin(fp1), end(fp1));
    return ans;
  }

  auto bridge = find_edge_between(fp1, fp2);
  if (!bridge) {
    return fp1.size() > fp2.size() ? fp1 : fp2;
  }

  auto left_end_iter = find(begin(fp2), end(fp2), bridge->second);
  rotate(begin(fp2), left_end_iter, end(fp2));

  auto right_end_iter = find(begin(fp1), end(fp1), bridge->first);
  rotate(begin(fp1), right_end_iter, end(fp1));

  vector<int> ans = fp2;
  reverse(begin(ans), end(ans));
  ans.insert(end(ans), begin(fp1), end(fp1));
  return ans;

  
}

Compilation message

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:56:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   56 |   if (fp1.size() == N) return fp1;
      |       ~~~~~~~~~~~^~~~
# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 4 ms 436 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 8 ms 344 KB Output is correct
2 Correct 9 ms 344 KB Output is correct
3 Correct 8 ms 344 KB Output is correct
4 Incorrect 2 ms 344 KB invalid array
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 8 ms 344 KB Output is correct
2 Correct 9 ms 344 KB Output is correct
3 Correct 9 ms 344 KB Output is correct
4 Incorrect 1 ms 344 KB invalid array
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 8 ms 344 KB Output is correct
2 Correct 9 ms 344 KB Output is correct
3 Correct 9 ms 344 KB Output is correct
4 Incorrect 1 ms 432 KB invalid array
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 8 ms 344 KB Output is correct
2 Correct 9 ms 344 KB Output is correct
3 Correct 6 ms 344 KB Output is correct
4 Incorrect 1 ms 344 KB invalid array
5 Halted 0 ms 0 KB -