Submission #1217885

#	Time	Username	Problem	Language	Result	Execution time	Memory
1217885		im2xtreme	Longest Trip (IOI23_longesttrip)	C++20	Compilation error	0 ms	0 KiB

longesttrip

#include <vector>
#include <algorithm>
using namespace std;

// Provided API
extern bool are_connected(const vector<int>& A, const vector<int>& B);

vector<vector<int>> adj;
vector<bool> visited;
vector<int> current_path, best_path;

void dfs(int u) {
    visited[u] = true;
    current_path.push_back(u);
    
    if (current_path.size() > best_path.size()) {
        best_path = current_path;
    }
    
    for (int v : adj[u]) {
        if (!visited[v]) {
            dfs(v);
        }
    }
    
    visited[u] = false;
    current_path.pop_back();
}

int* longest_trip(int N, int D) {
    adj = vector<vector<int>>(N);

    // Step 1: Discover edges using are_connected
    for (int i = 0; i < N; ++i) {
        for (int j = i + 1; j < N; ++j) {
            vector<int> A = {i}, B = {j};
            if (are_connected(A, B)) {
                adj[i].push_back(j);
                adj[j].push_back(i);
            }
        }
    }

    // Step 2: Run DFS from all nodes
    visited = vector<bool>(N, false);
    best_path.clear();
    
    for (int i = 0; i < N; ++i) {
        current_path.clear();
        dfs(i);
    }

    // Step 3: Convert vector to static array
    int* result = new int[best_path.size()];
    for (int i = 0; i < (int)best_path.size(); ++i) {
        result[i] = best_path[i];
    }

    return result;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccRR7TMi.o: in function `longest_trip(int, int)':
longesttrip.cpp:(.text+0x45a): undefined reference to `are_connected(std::vector<int, std::allocator<int> > const&, std::vector<int, std::allocator<int> > const&)'
collect2: error: ld returned 1 exit status