Submission #1024550

#	Time	Username	Problem	Language	Result	Execution time	Memory
1024550		Issa	Thousands Islands (IOI22_islands)	C++17	0 / 100	4 ms	12132 KiB

islands

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
pair<int, int> pii;

const int maxn = 2e5 + 100;

int n;
vector<int> g[maxn];
vector<int> gr[maxn];
int comp[maxn];
int sz[maxn];
vector<int> ord;
int used[maxn];

void dfs(int v){
    used[v] = 1;
    for(int to: g[v]){
        if(!used[to]) dfs(to);
    }
    ord.push_back(v);
}

void get(int v, int c){
    comp[v] = c; sz[c]++;
    for(int to: gr[v]){
        if(!comp[to]) get(to, c);
    }
}

int DFS(int v){
    if(used[v]) return 0;
    used[v] = 1;
    if(sz[comp[v]] > 1) return 1;
    for(int to: g[v]){
        if(DFS(to)) return 1;
    }
    return 0;
}

std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V){
    n = N;
    for(int i = 0; i < M; i++){
        int a = U[i] + 1, b = V[i] + 1;
        g[a].push_back(b);
        gr[b].push_back(a);
    }
    reverse(ord.begin(), ord.end());
    int c = 0;
    for(int v: ord){
        if(!comp[v]){
            c++;
            get(v, c);
        }
    }
    fill(used, used + n + 1, 0);
    return bool(DFS(1));
}

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