Submission #1077023

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077023		mariaclara	Thousands Islands (IOI22_islands)	C++17	0 / 100	23 ms	6488 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, at;
vector<vector<pii>> edges;

pii dfs(int x, int pai) {
    vis[x] = 1;
    if(pai != -1) at.pb(pai);
    
    vector<int> e;
    for(auto [viz,ind] : edges[x]) if(ind/2 != pai/2) e.pb(ind);
    if(sz(e) >= 2) return {e[0], e[1]};

    for(auto [viz,ind] : edges[x]){
        if(vis[viz]) continue;
        pii a = dfs(viz, ind);
        if(a.fr != -1) return a;
    }

    at.pop_back();
    return {-1,-1};
}
variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    edges.resize(N);
    vis.resize(N);
 
    for(int i = 0; i < M; i++)  edges[U[i]].pb({V[i], i});
 
    auto [a,b] = dfs(0, -1);
    if(a == -1) return false;

    vector<int> ans;

    for(int i = 0; i < sz(at); i++) ans.pb(at[i]);

    int c = a + 1 - 2*(a%2), d = b + 1 - 2*(b%2);
    ans.pb(a);
    ans.pb(c);
    ans.pb(b);
    ans.pb(d);
    ans.pb(c);
    ans.pb(a);
    ans.pb(d);
    ans.pb(b);

    for(int i = sz(at) - 1; i >= 0; i--) ans.pb(at[i]);

    return ans;
}

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