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Submission #252597

# Submission time Handle Problem Language Result Execution time Memory
252597 2020-07-25T21:46:40 Z Kubin Parachute rings (IOI12_rings) C++17
100 / 100
 2267 ms 212884 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;

bool verybad = false;
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] > 3 or base.deg[v] > 3) and w3 == SIZE_MAX)
        drop_w3 = current_forest_with_drop(w3 = (base.deg[u] > 3 ? u : v));
    else if(w3 != SIZE_MAX and u != w3 and v != w3)
        drop_w3.edge(u, v);

    if(w3 != SIZE_MAX and base.deg[u] > 3 and u != w3)
        verybad = true;
    if(w3 != SIZE_MAX and base.deg[v] > 3 and v != w3)
        verybad = true;

    if((base.deg[u] > 2 or base.deg[v] > 2) and w2 == SIZE_MAX and w3 == SIZE_MAX)
    {
        w2 = base.deg[u] > 2 ? u : v;
        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(verybad)
        return 0;
    else 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(w3 != SIZE_MAX)
            return drop_w3.status == Ok;

        size_t result = 0;
        for(auto& [_, F] : drop_w2s)
            result += F.status == Ok;
        return result;
    }
}

Compilation message

rings.cpp: In function 'int CountCritical()':
rings.cpp:155:24: warning: unused variable '_' [-Wunused-variable]
         for(auto& [_, F] : drop_w2s)
                        ^

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 3 ms 1280 KB Output is correct
3 Correct 4 ms 1536 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 5 ms 1024 KB Output is correct
7 Correct 1 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 4 ms 1408 KB Output is correct
10 Correct 4 ms 1536 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 515 ms 49720 KB Output is correct
2 Correct 1510 ms 170812 KB Output is correct
3 Correct 1539 ms 212884 KB Output is correct
4 Correct 1318 ms 94408 KB Output is correct
5 Correct 1331 ms 94544 KB Output is correct
6 Correct 1315 ms 92744 KB Output is correct
7 Correct 1629 ms 211268 KB Output is correct
8 Correct 2164 ms 195332 KB Output is correct
9 Correct 2267 ms 210952 KB Output is correct
10 Correct 899 ms 91852 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 3 ms 1280 KB Output is correct
3 Correct 4 ms 1536 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 5 ms 1024 KB Output is correct
7 Correct 1 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 4 ms 1408 KB Output is correct
10 Correct 4 ms 1536 KB Output is correct
11 Correct 4 ms 1536 KB Output is correct
12 Correct 8 ms 2704 KB Output is correct
13 Correct 7 ms 2584 KB Output is correct
14 Correct 5 ms 2452 KB Output is correct
15 Correct 8 ms 4128 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 7 ms 2456 KB Output is correct
18 Correct 9 ms 4384 KB Output is correct
19 Correct 7 ms 1536 KB Output is correct
20 Correct 7 ms 2708 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 3 ms 1280 KB Output is correct
3 Correct 4 ms 1536 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 5 ms 1024 KB Output is correct
7 Correct 1 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 4 ms 1408 KB Output is correct
10 Correct 4 ms 1536 KB Output is correct
11 Correct 4 ms 1536 KB Output is correct
12 Correct 8 ms 2704 KB Output is correct
13 Correct 7 ms 2584 KB Output is correct
14 Correct 5 ms 2452 KB Output is correct
15 Correct 8 ms 4128 KB Output is correct
16 Correct 5 ms 1408 KB Output is correct
17 Correct 7 ms 2456 KB Output is correct
18 Correct 9 ms 4384 KB Output is correct
19 Correct 7 ms 1536 KB Output is correct
20 Correct 7 ms 2708 KB Output is correct
21 Correct 21 ms 4344 KB Output is correct
22 Correct 36 ms 6640 KB Output is correct
23 Correct 72 ms 8316 KB Output is correct
24 Correct 91 ms 18484 KB Output is correct
25 Correct 31 ms 17416 KB Output is correct
26 Correct 71 ms 19276 KB Output is correct
27 Correct 63 ms 8684 KB Output is correct
28 Correct 111 ms 17368 KB Output is correct
29 Correct 61 ms 19184 KB Output is correct
30 Correct 81 ms 10092 KB Output is correct

Subtask #5
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 3 ms 1280 KB Output is correct
3 Correct 4 ms 1536 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 2 ms 640 KB Output is correct
6 Correct 5 ms 1024 KB Output is correct
7 Correct 1 ms 1152 KB Output is correct
8 Correct 2 ms 768 KB Output is correct
9 Correct 4 ms 1408 KB Output is correct
10 Correct 4 ms 1536 KB Output is correct
11 Correct 515 ms 49720 KB Output is correct
12 Correct 1510 ms 170812 KB Output is correct
13 Correct 1539 ms 212884 KB Output is correct
14 Correct 1318 ms 94408 KB Output is correct
15 Correct 1331 ms 94544 KB Output is correct
16 Correct 1315 ms 92744 KB Output is correct
17 Correct 1629 ms 211268 KB Output is correct
18 Correct 2164 ms 195332 KB Output is correct
19 Correct 2267 ms 210952 KB Output is correct
20 Correct 899 ms 91852 KB Output is correct
21 Correct 4 ms 1536 KB Output is correct
22 Correct 8 ms 2704 KB Output is correct
23 Correct 7 ms 2584 KB Output is correct
24 Correct 5 ms 2452 KB Output is correct
25 Correct 8 ms 4128 KB Output is correct
26 Correct 5 ms 1408 KB Output is correct
27 Correct 7 ms 2456 KB Output is correct
28 Correct 9 ms 4384 KB Output is correct
29 Correct 7 ms 1536 KB Output is correct
30 Correct 7 ms 2708 KB Output is correct
31 Correct 21 ms 4344 KB Output is correct
32 Correct 36 ms 6640 KB Output is correct
33 Correct 72 ms 8316 KB Output is correct
34 Correct 91 ms 18484 KB Output is correct
35 Correct 31 ms 17416 KB Output is correct
36 Correct 71 ms 19276 KB Output is correct
37 Correct 63 ms 8684 KB Output is correct
38 Correct 111 ms 17368 KB Output is correct
39 Correct 61 ms 19184 KB Output is correct
40 Correct 81 ms 10092 KB Output is correct
41 Correct 260 ms 35808 KB Output is correct
42 Correct 968 ms 155936 KB Output is correct
43 Correct 411 ms 157336 KB Output is correct
44 Correct 1292 ms 194496 KB Output is correct
45 Correct 1210 ms 201152 KB Output is correct
46 Correct 881 ms 78272 KB Output is correct
47 Correct 1137 ms 79684 KB Output is correct
48 Correct 787 ms 188820 KB Output is correct
49 Correct 872 ms 84632 KB Output is correct
50 Correct 900 ms 84052 KB Output is correct
51 Correct 463 ms 137684 KB Output is correct
52 Correct 1199 ms 138276 KB Output is correct
53 Correct 799 ms 188624 KB Output is correct
54 Correct 2056 ms 157636 KB Output is correct
55 Correct 1585 ms 186560 KB Output is correct