oj.uz

Submission #1019638

# Submission time Handle Problem Language Result Execution time Memory
1019638 2024-07-11T06:24:37 Z bobbilyking Longest Trip (IOI23_longesttrip) C++17
5 / 100
 915 ms 736 KB 
#include "longesttrip.h"
using namespace std;
#include <bits/stdc++.h>

#define F(i, l, r) for (int i = (l); i < (r); ++i)
#define A(a) (a).begin(), (a).end()

int edge[300][300];
int parent[300];
int find(int i) {
    return i == parent[i] ? i : parent[i] = find(parent[i]);
}

int GN;

bool query(int A, int B) {
    assert(min(A, B) >= 0 and max(A, B) < GN);
    return edge[A][B] | edge[B][A];
}

vector<int> longest_trip(int N, int ______________)
{
    GN = N;
    // okay we're just going to build the spanning tree straight up, fuck this shit. 
    iota(parent, parent + N, 0ll);
    
    F(i, 0, N) F(j, i + 1, N) {
        if (are_connected({i}, {j})) {
            parent[find(i)] = find(j);
            edge[i][j] = edge[j][i] = 1;
        }
    }

    F(i, 0, N) if (find(i) != find(0)) {
        vector<int> v[2];
        F(j, 0, N) v[find(j) == find(0)].push_back(j);
        if (v[0].size() < v[1].size()) swap(v[0], v[1]);
        return v[0];
    }

    vector<int> hamil;

    auto gen = [&]() {
        set<int> v;
        F(i, 0, N) if (find(A(hamil), i) == hamil.end()) v.insert(i);
        return v;
    };

    if (query({0}, {1})) {
        hamil = {0, 1};
    } else if (query({1}, {2})) {
        hamil = {1, 2};
    } else {
        hamil = {0, 2};
    }

    while (hamil.size() != N) { // this will reach N, with the exception of one case 
        // cout << "HOW " << endl;

        F(i, 1, hamil.size()) assert(query(hamil[i-1], hamil[i]));

        if (query({hamil[0]}, {hamil.back()})) {
            // its true that we have a hamiltonian CYCLE, so any rotation is valid. 
        } else {
            // Pick any node not in hamil, this must be connected to either the front or the back.
            auto i = *gen().begin();
            if (query({hamil[0]}, {i})) hamil.insert(hamil.begin(), i);
            else hamil.push_back(i);
            
            continue;
        }

        // Okay, we want to find *any* connection between hamil and others, if exists already. 
        auto bad = gen();

        bool seen_edge = false;
        F(___, 0, hamil.size()) {
            auto v = hamil.back(); hamil.pop_back(); hamil.insert(hamil.begin(), v);
            for (auto y: bad) if (edge[v][y]) {
                hamil.insert(hamil.begin(), y);
                seen_edge = true; 
                goto end;
            }
        }
        end: 

        assert(seen_edge); // we already handle the CC = 2 case up there in this brute force approach
    }


    return hamil;
}

Compilation message

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:57:25: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   57 |     while (hamil.size() != N) { // this will reach N, with the exception of one case
      |            ~~~~~~~~~~~~~^~~~
longesttrip.cpp:5:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define F(i, l, r) for (int i = (l); i < (r); ++i)
      |                                        ^
longesttrip.cpp:60:9: note: in expansion of macro 'F'
   60 |         F(i, 1, hamil.size()) assert(query(hamil[i-1], hamil[i]));
      |         ^
longesttrip.cpp:5:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define F(i, l, r) for (int i = (l); i < (r); ++i)
      |                                        ^
longesttrip.cpp:77:9: note: in expansion of macro 'F'
   77 |         F(___, 0, hamil.size()) {
      |         ^

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 205 ms 736 KB Output is correct

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 344 KB Output is correct
2 Correct 20 ms 344 KB Output is correct
3 Correct 165 ms 504 KB Output is correct
4 Correct 432 ms 564 KB Output is correct
5 Correct 915 ms 716 KB Output is correct

Subtask #2
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 344 KB Output is correct
2 Correct 29 ms 344 KB Output is correct
3 Correct 158 ms 344 KB Output is correct
4 Correct 463 ms 592 KB Output is correct
5 Correct 914 ms 716 KB Output is correct
6 Incorrect 1 ms 344 KB Incorrect
7 Halted 0 ms 0 KB -

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 344 KB Output is correct
2 Correct 22 ms 596 KB Output is correct
3 Correct 168 ms 344 KB Output is correct
4 Correct 454 ms 560 KB Output is correct
5 Correct 862 ms 716 KB Output is correct
6 Incorrect 1 ms 344 KB Incorrect
7 Halted 0 ms 0 KB -

Subtask #4
0.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 344 KB Output is correct
2 Correct 32 ms 344 KB Output is correct
3 Partially correct 171 ms 344 KB Output is partially correct
4 Partially correct 415 ms 344 KB Output is partially correct
5 Partially correct 885 ms 716 KB Output is partially correct
6 Incorrect 1 ms 344 KB Incorrect
7 Halted 0 ms 0 KB -