Submission #1077002

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077002		mariaclara	Thousands Islands (IOI22_islands)	C++17	8.40 / 100	30 ms	6492 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair<int,int> pii;
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define pb push_back
#define mk make_pair
#define fr first
#define sc second
 
vector<int> vis, block;
vector<vector<pii>> edges;

vector<int> dfs(int x) {
    vis[x] = 1;
 
    for(auto [viz,ind] : edges[x]) {
        if(block[viz]) continue;
        if(vis[viz]) return {ind};
        
        vector<int> v = dfs(viz);
        if(!v.empty()) {v.pb(ind); return v;}
    }

    block[x] = 1;
    return {};
}
variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    edges.resize(N);
    vis.resize(N);
    block.resize(N);
 
    for(int i = 0; i < M; i += 2)  edges[U[i]].pb({V[i], i});
 
    vector<int> c = dfs(0), ans;
    if(c.empty()) return false;
    reverse(all(c));

    int x = V[c.back()], m = 0;

    for(int i = sz(c) - 1; i >= 0; i--) if(U[i] == x) m = i;

    // PARTE 1
    for(int i = 0; i < sz(c); i++) ans.pb(c[i]);
    for(int i = m-1; i >= 0; i--) ans.pb(c[i]);

    // PARTE 2
    for(int i = 0; i < sz(c); i++) ans.pb(c[i] + 1);
    for(int i = m-1; i >= 0; i--) ans.pb(c[i] + 1);

    // PARTE 3
    for(int i = 0; i < m; i++) ans.pb(c[i]);
    for(int i = sz(c) - 1; i >= m; i--) ans.pb(c[i]);
    for(int i = m-1; i >= 0; i--) ans.pb(c[i]);

    // PARTE 4
    for(int i = 0; i < m; i++) ans.pb(c[i] + 1);
    for(int i = sz(c) - 1; i >= m; i--) ans.pb(c[i] + 1);
    for(int i = m-1; i >= 0; i--) ans.pb(c[i] + 1);

    return ans;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 8.399999999999999 / 24
• Subtask 5: 0 / 45