Submission #1067219

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067219		j_vdd16	Thousands Islands (IOI22_islands)	C++17	0 / 100	2 ms	1276 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;
vvii adj;

vb vis;
vi succesPath;

vi depths;
int counter = 0;
vii inOut;
void dfs(int node, int d, int parent) {
    vis[node] = true;
    depths[node] = d;
 
    inOut[node].first = counter++;
 
    for (auto [child, idx] : adj[node]) {
        if (child == parent || vis[child]) continue;
 
        dfs(child, d + 1, node);
    }
 
    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;
vi path;
vvi marked;
int dfs2(int node, int parent) {
    if (vis[node]) {
        marked[node] = path;
        return 1;
    }
    
    vis[node] = true;
    marked[node] = {};

    int count = 0;
    vi validPaths;
    for (auto [child, idx] : adj[node]) {
        if (idx % 2) continue;
        
        path.push_back(idx);
        int res = dfs2(child, node);
        path.pop_back();

        if (res >= 1 && count < 2) {
            count++;
            validPaths.push_back(idx);
        }
    }

    if (marked[node].size() && !success) {
        success = true;

        succesPath = marked[node];
        for (int i = path.size(); i < marked[node].size(); i++) {
            succesPath.push_back(marked[node][i] ^ 1);
        }
        for (int i = marked[node].size(); i >= path.size(); i++) {
            succesPath.push_back(marked[node][i]);
        }
        for (int i = marked[node].size(); i >= path.size(); i++) {
            succesPath.push_back(marked[node][i] ^ 1);
        }

        for (int i = path.size() - 1; i >= 0; i--) {
            succesPath.push_back(path[i]);
        }
    }

    if (count >= 2 && !success) {
        //success = true;
        // succesPath = path;
        
        // succesPath.push_back(validPaths[0]);
        // succesPath.push_back(validPaths[0] ^ 1);
        // succesPath.push_back(validPaths[1]);
        // succesPath.push_back(validPaths[1] ^ 1);

        // succesPath.push_back(validPaths[0] ^ 1);
        // succesPath.push_back(validPaths[0]);
        // succesPath.push_back(validPaths[1] ^ 1);
        // succesPath.push_back(validPaths[1]);

        // for (int i = path.size() - 1; i >= 0; i--) {
        //     succesPath.push_back(path[i]);
        // }
    }

    return 1;
}

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});
    }

    vis = vb(n);
    success = false;
    path = vi();
    marked = vvi(n);
    dfs2(0, -1);

    if (success) {
        for (int x : succesPath) {
            cerr << x << ' ';
        }
        cerr << endl;
        return succesPath;
    }
    return false;

    // return false;

    // return success;
}

Compilation message (stderr)

islands.cpp: In function 'int dfs2(int, int)':
islands.cpp:96:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   96 |         for (int i = path.size(); i < marked[node].size(); i++) {
      |                                   ~~^~~~~~~~~~~~~~~~~~~~~
islands.cpp:99:45: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |         for (int i = marked[node].size(); i >= path.size(); i++) {
      |                                           ~~^~~~~~~~~~~~~~
islands.cpp:102:45: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |         for (int i = marked[node].size(); i >= path.size(); i++) {
      |                                           ~~^~~~~~~~~~~~~~

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