Submission #1067133

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067133		j_vdd16	Thousands Islands (IOI22_islands)	C++17	0 / 100	1 ms	448 KiB

islands

#include "islands.h"

#include <variant>
#include <algorithm>
#include <bitset>
#include <cstdint>
#include <cstring>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

//#define int long long
#define loop(X, N) for(int X = 0; X < (N); X++)
#define all(V) V.begin(), V.end()
#define rall(V) V.rbegin(), V.rend()

using namespace std;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;

typedef uint64_t u64;
typedef int64_t i64;

int n, m;
vvi adj1;//adj2;

vb vis;
vi depths;

int counter = 0;
vii inOut;
void dfs(int node, int d) {
    if (vis[node]) {
        return;
    }
    vis[node] = true;
    depths[node] = d;

    inOut[node].first = counter++;

    for (int child : adj1[node]) {
        dfs(node, d + 1);
    }

    inOut[node].second = counter++;
}

bool isAncestor(int a, int b) {
    return inOut[a].first <= inOut[b].first && inOut[b].first <= inOut[a].second;
}

bool success = false;
// bool isPossible(int node) {
//     if (vis[node]) {
//         return {node, false};
//     }
//     vis[node] = true;

//     int closestBack = node;
//     int cycleCount = 0;
//     for (int child : adj1[node]) {
//         auto [res, pos] = isPossible(child);
//         if (isAncestor(node, res)) {
//             cycleCount++;
//         }

//         if (isAncestor(node, res) && depths[closestBack] < depths[res]) {
//             closestBack = res;
//         }
//     }

//     if (cycleCount >= 2) {
//         success = true;
//     }

//     return {closestBack, };
// }

vvii adj;
std::variant<bool, std::vector<int>> find_journey(int N, int M, vi U, vi V) {
    n = N;
    m = M;
    adj = vvii(n);
    loop(i, m) {
        adj[U[i]].push_back({V[i], i});
    }

    if (n == 2) {
        if (adj[0].size() < 2 || adj[1].size() < 2) {
            return false;
        }
        return vi{ adj[0][0].second, adj[1][0].second, adj[0][1].second, adj[1][1].second, adj[0][0].second, adj[1][0].second, adj[0][1].second, adj[1][1].second };
    }

    return false;

    // vis = vb(n);
    // depths = vi(n);
    // counter = 0;
    // inOut = vii(n);
    // dfs(0, 0);
    // vis = vb(n);
    // marked = vi(n);
    // success = false;
    // isPossible(0);

    // return success;
}

Compilation message (stderr)

islands.cpp: In function 'void dfs(int, int)':
islands.cpp:54:14: warning: unused variable 'child' [-Wunused-variable]
   54 |     for (int child : adj1[node]) {
      |              ^~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45