Submission #1242798

#	Time	Username	Problem	Language	Result	Execution time	Memory
1242798		Zbyszek99	Thousands Islands (IOI22_islands)	C++20	35 / 100	51 ms	15548 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace std;
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

int out_deg[100001];
vi in_graph[100001];
bool del[100001];
vector<pii> out_graph[100001];
queue<int> events;
vi ans;
int beg_path_siz = 0;

void del_vert(int x)
{
    del[x] = 1;
    forall(it,in_graph[x])
    {
        out_deg[it]--;
        if(out_deg[it] == 0) events.push(it);
    }
}

int new_beg(int v)
{
    int v2 = -1;
    forall(it,out_graph[v])
    {
        if(del[it.ff]) continue;
        v2 = it.ff;
        beg_path_siz++;
        ans.pb(it.ss);
    }
    del_vert(v);
    return v2;
}

variant<bool,vi> find_journey(int n, int m, vi u, vi v) 
//vi find_journey(int n, int m, vi u, vi v)
{
    rep(i,m)
    {
        out_graph[u[i]].pb({v[i],i});
    }
    rep(i,m)
    {
        out_deg[u[i]]++;
        in_graph[v[i]].pb(u[i]);
    }
    rep(i,n)
    {
        if(out_deg[i] == 0) events.push(i);
    }
    int cur_beg = 0;
    while(out_deg[cur_beg] <= 1)
    {
        int nb = new_beg(cur_beg);
        if(nb == -1) return (bool)0;
        cur_beg = nb;
    }
    while(!events.empty())
    {
        int x = events.front();
        events.pop();
        if(del[x]) continue;
        del_vert(x);
        while(out_deg[cur_beg] <= 1)
        {
            int nb = new_beg(cur_beg);
            if(nb == -1) return (bool)0;
            cur_beg = nb;
        }
    }
    return ans;
}

• Subtask 1: 1.75 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 7.35 / 21
• Subtask 4: 8.4 / 24
• Subtask 5: 15.75 / 45