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Submission #252594

# Submission time Handle Problem Language Result Execution time Memory
252594 2020-07-25T21:42:38 Z Kubin Parachute rings (IOI12_rings) C++17
100 / 100
 2412 ms 230384 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;
        for(auto& [_, F] : drop_w2s)
            result += F.status == Ok;
        return result;
    }
}

Compilation message

rings.cpp: In function 'int CountCritical()':
rings.cpp:154:24: 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 256 KB Output is correct
2 Correct 3 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 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 1408 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 669 ms 49232 KB Output is correct
2 Correct 1581 ms 170572 KB Output is correct
3 Correct 1951 ms 230384 KB Output is correct
4 Correct 1337 ms 94396 KB Output is correct
5 Correct 1436 ms 94408 KB Output is correct
6 Correct 1415 ms 92648 KB Output is correct
7 Correct 1911 ms 228364 KB Output is correct
8 Correct 2219 ms 195220 KB Output is correct
9 Correct 2412 ms 210972 KB Output is correct
10 Correct 901 ms 91656 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 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 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 1408 KB Output is correct
11 Correct 4 ms 1536 KB Output is correct
12 Correct 8 ms 2576 KB Output is correct
13 Correct 10 ms 2580 KB Output is correct
14 Correct 5 ms 2324 KB Output is correct
15 Correct 7 ms 4128 KB Output is correct
16 Correct 6 ms 1408 KB Output is correct
17 Correct 8 ms 2328 KB Output is correct
18 Correct 10 ms 4384 KB Output is correct
19 Correct 5 ms 1408 KB Output is correct
20 Correct 8 ms 2580 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 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 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 1408 KB Output is correct
11 Correct 4 ms 1536 KB Output is correct
12 Correct 8 ms 2576 KB Output is correct
13 Correct 10 ms 2580 KB Output is correct
14 Correct 5 ms 2324 KB Output is correct
15 Correct 7 ms 4128 KB Output is correct
16 Correct 6 ms 1408 KB Output is correct
17 Correct 8 ms 2328 KB Output is correct
18 Correct 10 ms 4384 KB Output is correct
19 Correct 5 ms 1408 KB Output is correct
20 Correct 8 ms 2580 KB Output is correct
21 Correct 23 ms 4088 KB Output is correct
22 Correct 41 ms 6384 KB Output is correct
23 Correct 64 ms 8044 KB Output is correct
24 Correct 101 ms 18680 KB Output is correct
25 Correct 53 ms 17384 KB Output is correct
26 Correct 93 ms 19144 KB Output is correct
27 Correct 55 ms 8556 KB Output is correct
28 Correct 126 ms 17756 KB Output is correct
29 Correct 62 ms 19568 KB Output is correct
30 Correct 114 ms 10732 KB Output is correct

Subtask #5
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 3 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 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 1408 KB Output is correct
11 Correct 669 ms 49232 KB Output is correct
12 Correct 1581 ms 170572 KB Output is correct
13 Correct 1951 ms 230384 KB Output is correct
14 Correct 1337 ms 94396 KB Output is correct
15 Correct 1436 ms 94408 KB Output is correct
16 Correct 1415 ms 92648 KB Output is correct
17 Correct 1911 ms 228364 KB Output is correct
18 Correct 2219 ms 195220 KB Output is correct
19 Correct 2412 ms 210972 KB Output is correct
20 Correct 901 ms 91656 KB Output is correct
21 Correct 4 ms 1536 KB Output is correct
22 Correct 8 ms 2576 KB Output is correct
23 Correct 10 ms 2580 KB Output is correct
24 Correct 5 ms 2324 KB Output is correct
25 Correct 7 ms 4128 KB Output is correct
26 Correct 6 ms 1408 KB Output is correct
27 Correct 8 ms 2328 KB Output is correct
28 Correct 10 ms 4384 KB Output is correct
29 Correct 5 ms 1408 KB Output is correct
30 Correct 8 ms 2580 KB Output is correct
31 Correct 23 ms 4088 KB Output is correct
32 Correct 41 ms 6384 KB Output is correct
33 Correct 64 ms 8044 KB Output is correct
34 Correct 101 ms 18680 KB Output is correct
35 Correct 53 ms 17384 KB Output is correct
36 Correct 93 ms 19144 KB Output is correct
37 Correct 55 ms 8556 KB Output is correct
38 Correct 126 ms 17756 KB Output is correct
39 Correct 62 ms 19568 KB Output is correct
40 Correct 114 ms 10732 KB Output is correct
41 Correct 305 ms 39136 KB Output is correct
42 Correct 938 ms 160976 KB Output is correct
43 Correct 406 ms 160664 KB Output is correct
44 Correct 1128 ms 206600 KB Output is correct
45 Correct 1361 ms 215872 KB Output is correct
46 Correct 879 ms 89608 KB Output is correct
47 Correct 1149 ms 91200 KB Output is correct
48 Correct 804 ms 195884 KB Output is correct
49 Correct 847 ms 94412 KB Output is correct
50 Correct 968 ms 93544 KB Output is correct
51 Correct 451 ms 141268 KB Output is correct
52 Correct 1310 ms 148772 KB Output is correct
53 Correct 820 ms 195792 KB Output is correct
54 Correct 2265 ms 163340 KB Output is correct
55 Correct 1622 ms 198580 KB Output is correct