Submission #652849

#	Time	Username	Problem	Language	Result	Execution time	Memory
652849		Lobo	Thousands Islands (IOI22_islands)	C++17	0 / 100	6 ms	9976 KiB

islands

#include "islands.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back

const int maxn = 2e5+10;
int n, m, tin[maxn], low[maxn], mark[maxn], can[maxn], timer;
vector<int> g[maxn], gt[maxn];

void dfsscc(int u) {
    tin[u] = ++timer;
    low[u] = tin[u];
    for(auto v : g[u]) {
        if(mark[v] != 0 && mark[v] != mark[u]) continue;
        if(mark[v] != 0) {
            low[v] = min(low[v],tin[u]);
        }
        else {
            mark[v] = mark[u];
            dfsscc(v);
            low[u] = min(low[u],low[v]);
        }
    }
}

variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    n = N;
    m = M;
    for(int i = 0; i < m; i++) {
        g[U[i]].pb(V[i]);
        gt[V[i]].pb(U[i]);
    }

    int cntm = 0;
    for(int i = 0; i < m; i++) {
        if(!mark[i]) {
            mark[i] = ++cntm;
            dfsscc(i);
        }
    }

    for(int i = 0; i < m; i++) {
        can[i] = 0;
        if(low[i] < tin[i]) can[i] = 1;
    }
    return (can[0] == 1);

    // if (N == 4) {
    // return std::vector<int>({0, 1, 2, 4, 0, 3, 2, 1, 4, 3});
    // }
    // return false;
}

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