Submission #824307

#	Time	Username	Problem	Language	Result	Execution time	Memory
824307		vjudge1	Thousands Islands (IOI22_islands)	C++17	12.35 / 100	33 ms	12804 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
vector<int> adj[200100];
int ind[1000][1000];
bool vis[1000];
vector<int> ans;
bool dfs(int n, int p) {
    if(vis[n]) return 0;
    vis[n] = 1;
    if(adj[n].size()>2-!(p+1)) {
        int a=-1, b, c=-1, d;
        for(auto i: adj[n])
            if(i!=p) {
                if(a<0)
                    a = ind[n][i], b = ind[i][n];
                else if(c<0)
                    c = ind[n][i], d = ind[i][n];
            }
        ans.push_back(a);
        ans.push_back(b);
        ans.push_back(c);
        ans.push_back(d);
        ans.push_back(b);
        ans.push_back(a);
        ans.push_back(d);
        ans.push_back(c);
        return 1;
    }
    for(auto i: adj[n]) {
        ans.push_back(ind[i][n]);
        if(dfs(i, n)) {
            ans.push_back(ind[i][n]);
            return 1;
        }
        ans.pop_back();
    }
    return 0;
}
variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    for(int i = 0; i < M; i++)
        adj[U[i]].push_back(V[i]), ind[U[i]][V[i]] = i;
    if(dfs(0,-1)) {
        return ans;
    } else {
        return false;
    }
}

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 7.35 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45