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Submission #252593

# Submission time Handle Problem Language Result Execution time Memory
252593 2020-07-25T21:42:06 Z Kubin Parachute rings (IOI12_rings) C++17
55 / 100
 4000 ms 230468 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)
{
    size_t u = _u, v = _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 u != w3 and 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)});
        for(size_t i = 0; i < graph[w2].size(); i++)
            drop_w2s[1+i] = {graph[w2][i], current_forest_with_drop(graph[w2][i])};
        drop_w2s[0] = {w2, current_forest_with_drop(w2)};
    }
    else if(w3 == SIZE_MAX and w2 != SIZE_MAX)
    {
        for(auto& [w, F] : drop_w2s)
            if(u != w and v != w)
                F.edge(u, v);
    }
}

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 4 ms 1280 KB Output is correct
3 Correct 3 ms 1536 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 2 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 5 ms 1536 KB Output is correct
10 Correct 5 ms 1408 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 572 ms 49380 KB Output is correct
2 Correct 1508 ms 170324 KB Output is correct
3 Correct 1898 ms 230468 KB Output is correct
4 Correct 1326 ms 94320 KB Output is correct
5 Correct 1345 ms 94408 KB Output is correct
6 Correct 1350 ms 92544 KB Output is correct
7 Correct 1862 ms 228352 KB Output is correct
8 Correct 2896 ms 202376 KB Output is correct
9 Correct 3348 ms 218596 KB Output is correct
10 Correct 902 ms 91584 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 4 ms 1280 KB Output is correct
3 Correct 3 ms 1536 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 2 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 5 ms 1536 KB Output is correct
10 Correct 5 ms 1408 KB Output is correct
11 Correct 15 ms 1536 KB Output is correct
12 Correct 13 ms 2576 KB Output is correct
13 Correct 32 ms 2584 KB Output is correct
14 Correct 5 ms 2452 KB Output is correct
15 Correct 7 ms 4128 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 59 ms 2632 KB Output is correct
18 Correct 15 ms 4448 KB Output is correct
19 Correct 6 ms 1408 KB Output is correct
20 Correct 45 ms 2572 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 4 ms 1280 KB Output is correct
3 Correct 3 ms 1536 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 2 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 5 ms 1536 KB Output is correct
10 Correct 5 ms 1408 KB Output is correct
11 Correct 15 ms 1536 KB Output is correct
12 Correct 13 ms 2576 KB Output is correct
13 Correct 32 ms 2584 KB Output is correct
14 Correct 5 ms 2452 KB Output is correct
15 Correct 7 ms 4128 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 59 ms 2632 KB Output is correct
18 Correct 15 ms 4448 KB Output is correct
19 Correct 6 ms 1408 KB Output is correct
20 Correct 45 ms 2572 KB Output is correct
21 Correct 22 ms 4216 KB Output is correct
22 Correct 36 ms 6384 KB Output is correct
23 Correct 54 ms 8044 KB Output is correct
24 Correct 76 ms 18680 KB Output is correct
25 Correct 42 ms 17344 KB Output is correct
26 Correct 610 ms 19256 KB Output is correct
27 Correct 55 ms 8556 KB Output is correct
28 Execution timed out 4062 ms 16760 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 4 ms 1280 KB Output is correct
3 Correct 3 ms 1536 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 2 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 5 ms 1536 KB Output is correct
10 Correct 5 ms 1408 KB Output is correct
11 Correct 572 ms 49380 KB Output is correct
12 Correct 1508 ms 170324 KB Output is correct
13 Correct 1898 ms 230468 KB Output is correct
14 Correct 1326 ms 94320 KB Output is correct
15 Correct 1345 ms 94408 KB Output is correct
16 Correct 1350 ms 92544 KB Output is correct
17 Correct 1862 ms 228352 KB Output is correct
18 Correct 2896 ms 202376 KB Output is correct
19 Correct 3348 ms 218596 KB Output is correct
20 Correct 902 ms 91584 KB Output is correct
21 Correct 15 ms 1536 KB Output is correct
22 Correct 13 ms 2576 KB Output is correct
23 Correct 32 ms 2584 KB Output is correct
24 Correct 5 ms 2452 KB Output is correct
25 Correct 7 ms 4128 KB Output is correct
26 Correct 5 ms 1408 KB Output is correct
27 Correct 59 ms 2632 KB Output is correct
28 Correct 15 ms 4448 KB Output is correct
29 Correct 6 ms 1408 KB Output is correct
30 Correct 45 ms 2572 KB Output is correct
31 Correct 22 ms 4216 KB Output is correct
32 Correct 36 ms 6384 KB Output is correct
33 Correct 54 ms 8044 KB Output is correct
34 Correct 76 ms 18680 KB Output is correct
35 Correct 42 ms 17344 KB Output is correct
36 Correct 610 ms 19256 KB Output is correct
37 Correct 55 ms 8556 KB Output is correct
38 Execution timed out 4062 ms 16760 KB Time limit exceeded
39 Halted 0 ms 0 KB -