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Submission #252592

# Submission time Handle Problem Language Result Execution time Memory
252592 2020-07-25T21:39:26 Z Kubin Parachute rings (IOI12_rings) C++17
55 / 100
 4000 ms 136540 KB 
#include <bits/stdc++.h>

using namespace std;

struct disjoint_sets
{
    vector<size_t> repr, rank;

    disjoint_sets(size_t n) : repr(n), rank(n)
    {
        for(size_t i = 0; i < n; i++)
            repr[i] = i;
    }

    size_t find(size_t v)
    {
        return v == repr[v] ? v : repr[v] = find(repr[v]);
    }

    bool unite(size_t u, size_t v)
    {
        if((u = find(u)) == (v = find(v)))
            return false;
        if(rank[u] > rank[v])
            swap(u, v);
        rank[v] += (rank[u] == rank[v]);
        repr[u] = v;
        return true;
    }
};

enum BambooForestStatus
{
    Ok,
    Cycles,
    Bad
};

struct bamboo_forest
{
    BambooForestStatus status = Ok;
    disjoint_sets dsets;
    vector<size_t> deg;
    size_t cycles = 0;

    bamboo_forest(size_t n) : dsets(n), deg(n) {}
    bamboo_forest() : bamboo_forest(0) {}

    BambooForestStatus edge(size_t u, size_t v)
    {
        deg[u]++; deg[v]++;
        if(deg[u] > 2 or deg[v] > 2)
            status = Bad;
        if((status == Ok or status == Cycles) and dsets.find(u) == dsets.find(v) and deg[u] == 2 and deg[v] == 2)
            status = Cycles, cycles++;
        else if(not dsets.unite(u, v))
            status = Bad;
        return status;
    }
};

size_t n;
vector<pair<size_t, size_t>> edges;
vector<vector<size_t>> graph;
bamboo_forest base;
size_t first_cycle_size;
unordered_set<size_t> greater2, greater3;

size_t w2 = SIZE_MAX, w3 = SIZE_MAX;
bamboo_forest drop_w3;
vector<pair<size_t, bamboo_forest>> drop_w2s;

void Init(int _n)
{
    n = _n;
    base = bamboo_forest(n);
    graph.resize(n);
}

bamboo_forest current_forest_with_drop(size_t w)
{
    bamboo_forest F(n);
    for(auto [u, v] : edges)
        if(u != w and v != w)
            F.edge(u, v);
    return F;
}

void Link(int u, int v)
{
    edges.emplace_back(u, v);
    graph[u].push_back(v);
    graph[v].push_back(u);

    auto pre = base.status;
    base.edge(u, v);

    if(pre == Ok and base.status == Cycles and base.cycles == 1)
    {
        auto w = base.dsets.find(u);
        for(size_t i = 0; i < n; i++)
            if(base.dsets.find(i) == w)
                first_cycle_size++;
    }
    if(base.deg[u] > 2) greater2.insert(u);
    if(base.deg[v] > 2) greater2.insert(v);
    if(base.deg[u] > 3) greater3.insert(u);
    if(base.deg[v] > 3) greater3.insert(v);

    if(not greater3.empty() and w3 == SIZE_MAX)
        drop_w3 = current_forest_with_drop(w3 = *greater3.begin());
    else if(w3 != SIZE_MAX and (size_t)u != w3 and (size_t)v != w3)
        drop_w3.edge(u, v);

    /*
    if(not greater2.empty() and w2 == SIZE_MAX and w3 == SIZE_MAX)
    {
        w2 = *greater2.begin();
        drop_w2s.resize(graph[w2].size() + 1, {SIZE_MAX, bamboo_forest(n)});

    }
    */
}

bool naive_try(size_t i)
{
    return current_forest_with_drop(i).status == Ok;
}

int CountCritical()
{
    if(base.status == Ok)
        return n;
    else if(base.status == Cycles and base.cycles == 1)
        return first_cycle_size;
    else if(base.status == Cycles and base.cycles > 1)
        return 0;
    else if(greater3.size() > 1)
        return 0;
    else
    {
        if(w3 != SIZE_MAX)
            return drop_w3.status == Ok;

        size_t result = 0, w = *greater2.begin();
        for(size_t i : graph[w])
            result += naive_try(i);
        result += naive_try(w);
        return result;
    }
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 ms 896 KB Output is correct
3 Correct 3 ms 1024 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 3 ms 896 KB Output is correct
7 Correct 1 ms 768 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 3 ms 1024 KB Output is correct
10 Correct 3 ms 1024 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 493 ms 49236 KB Output is correct
2 Correct 1240 ms 95380 KB Output is correct
3 Correct 2152 ms 136540 KB Output is correct
4 Correct 1355 ms 94488 KB Output is correct
5 Correct 1452 ms 94800 KB Output is correct
6 Correct 1302 ms 92752 KB Output is correct
7 Correct 1957 ms 134492 KB Output is correct
8 Correct 2419 ms 110436 KB Output is correct
9 Correct 2660 ms 118148 KB Output is correct
10 Correct 874 ms 92108 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 ms 896 KB Output is correct
3 Correct 3 ms 1024 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 3 ms 896 KB Output is correct
7 Correct 1 ms 768 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 3 ms 1024 KB Output is correct
10 Correct 3 ms 1024 KB Output is correct
11 Correct 13 ms 1024 KB Output is correct
12 Correct 12 ms 1688 KB Output is correct
13 Correct 33 ms 1648 KB Output is correct
14 Correct 5 ms 1536 KB Output is correct
15 Correct 6 ms 2304 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 62 ms 1776 KB Output is correct
18 Correct 13 ms 2584 KB Output is correct
19 Correct 6 ms 1536 KB Output is correct
20 Correct 41 ms 1696 KB Output is correct

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 ms 896 KB Output is correct
3 Correct 3 ms 1024 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 3 ms 896 KB Output is correct
7 Correct 1 ms 768 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 3 ms 1024 KB Output is correct
10 Correct 3 ms 1024 KB Output is correct
11 Correct 13 ms 1024 KB Output is correct
12 Correct 12 ms 1688 KB Output is correct
13 Correct 33 ms 1648 KB Output is correct
14 Correct 5 ms 1536 KB Output is correct
15 Correct 6 ms 2304 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 62 ms 1776 KB Output is correct
18 Correct 13 ms 2584 KB Output is correct
19 Correct 6 ms 1536 KB Output is correct
20 Correct 41 ms 1696 KB Output is correct
21 Correct 30 ms 4468 KB Output is correct
22 Correct 39 ms 6896 KB Output is correct
23 Correct 45 ms 8428 KB Output is correct
24 Correct 67 ms 10740 KB Output is correct
25 Correct 30 ms 8236 KB Output is correct
26 Correct 630 ms 11032 KB Output is correct
27 Correct 62 ms 9552 KB Output is correct
28 Execution timed out 4054 ms 8548 KB Time limit exceeded
29 Halted 0 ms 0 KB -

Subtask #5
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 ms 896 KB Output is correct
3 Correct 3 ms 1024 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 3 ms 896 KB Output is correct
7 Correct 1 ms 768 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 3 ms 1024 KB Output is correct
10 Correct 3 ms 1024 KB Output is correct
11 Correct 493 ms 49236 KB Output is correct
12 Correct 1240 ms 95380 KB Output is correct
13 Correct 2152 ms 136540 KB Output is correct
14 Correct 1355 ms 94488 KB Output is correct
15 Correct 1452 ms 94800 KB Output is correct
16 Correct 1302 ms 92752 KB Output is correct
17 Correct 1957 ms 134492 KB Output is correct
18 Correct 2419 ms 110436 KB Output is correct
19 Correct 2660 ms 118148 KB Output is correct
20 Correct 874 ms 92108 KB Output is correct
21 Correct 13 ms 1024 KB Output is correct
22 Correct 12 ms 1688 KB Output is correct
23 Correct 33 ms 1648 KB Output is correct
24 Correct 5 ms 1536 KB Output is correct
25 Correct 6 ms 2304 KB Output is correct
26 Correct 5 ms 1408 KB Output is correct
27 Correct 62 ms 1776 KB Output is correct
28 Correct 13 ms 2584 KB Output is correct
29 Correct 6 ms 1536 KB Output is correct
30 Correct 41 ms 1696 KB Output is correct
31 Correct 30 ms 4468 KB Output is correct
32 Correct 39 ms 6896 KB Output is correct
33 Correct 45 ms 8428 KB Output is correct
34 Correct 67 ms 10740 KB Output is correct
35 Correct 30 ms 8236 KB Output is correct
36 Correct 630 ms 11032 KB Output is correct
37 Correct 62 ms 9552 KB Output is correct
38 Execution timed out 4054 ms 8548 KB Time limit exceeded
39 Halted 0 ms 0 KB -