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Submission #1067651

# Submission time Handle Problem Language Result Execution time Memory
1067651 2024-08-20T22:50:33 Z golf Longest Trip (IOI23_longesttrip) C++17
85 / 100
 16 ms 1368 KB 
#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> solve_d3(int N, int D)
{
    vector<int> res(N);
    iota(res.begin(), res.end(), 0);
    return res;
}

vector<int> solve_d2(int N, int D)
{
    queue<int> stops;
    for (int i = 1; i < N; i++)
        stops.push(i);

    deque<int> trip = {0};
    while (stops.size() > 1)
    {
        int next = stops.front();
        stops.pop();
        int last = trip.back();

        if (are_connected({next}, {last}))
        {
            trip.push_back(next);
        }
        else
        {
            trip.push_back(stops.front());
            stops.pop();
            trip.push_back(next);
        }
    }

    if (stops.size() == 1)
    {
        int next = stops.front();
        int last = trip.back();
        if (are_connected({next}, {last}))
        {
            trip.push_back(next);
        }
        else
        {
            trip.push_front(stops.front());
            stops.pop();
        }
    }

    vector<int> res;
    for (int x : trip)
        res.push_back(x);
    return res;
}

int pop(queue<int> &q)
{
    int x = q.front();
    q.pop();
    return x;
}

const bool maybe = true;

map<pair<set<int>, set<int>>, bool> cache;
bool are_conn(vector<int> a, vector<int> b) {
    // if (a.size() != 1 || b.size() != 1) return are_connected(a, b);

    // int x = a[0], y = b[0];
    // if (x < y) swap(x, y);
    // if (cache.count({x, y})) return cache[{x, y}];

    // cache[{x, y}] = are_connected(a, b);
    // return cache[{x, y}];
    set<int> A, B;
    for (int x : a) A.insert(x);
    for (int x : b) B.insert(x);

    if (cache.count({A, B})) return cache[{A, B}];
    if (cache.count({B, A})) return cache[{B, A}];

    bool res = are_connected(a, b);
    cache[{A, B}] = res;
    cache[{B, A}] = res;
    return res;
}

vector<int> longest_trip(int N, int D)
{
    if (D == 3)
        return solve_d3(N, D);
    if (D == 2)
        return solve_d2(N, D);

    cache.clear();

    srand(time(0));
    vector<int> rand_nodes(N);
    iota(rand_nodes.begin(), rand_nodes.end(), 0);
    random_shuffle(rand_nodes.begin(), rand_nodes.end());

    queue<int> nodes;
    for (int x : rand_nodes)
        nodes.push(x);

    vector<int> a, b;
    a.push_back(pop(nodes));

    bool ends_connected = maybe;
    // false = a and b are not connected
    // true  = a and b are maybe connected
    while (!nodes.empty())
    {
        if (b.empty())
        {
            int n = pop(nodes);
            b.push_back(n);
            ends_connected = maybe;
            // if (are_conn({a.back()}, {n}))
            // {
            //     a.push_back(n);
            // }
            // else
            // {
            //     // missed optimization
            //     // we could cache that a and b are not connected
            //     b.push_back(n);
            //     ends_connected = false;
            // }
            // continue;
        }

        // both a and b are non-empty
        int n = pop(nodes);

        if (are_conn({a.back()}, {n}))
        {
            a.push_back(n);
            ends_connected = maybe;
        }
        else if (are_conn({b.back()}, {n}))
        {
            b.push_back(n);
            ends_connected = false;
        }
        else
        {
            // ends of a and b are definitely connected
            while (!b.empty())
            {
                a.push_back(b.back());
                b.pop_back();
            }

            assert(b.empty());
            b.push_back(n);
        }
    }

    if (b.empty())
    {
        return a;
    }

    if (ends_connected == maybe && are_conn({a.back()}, {b.back()}))
    {
        while (!b.empty())
        {
            a.push_back(b.back());
            b.pop_back();
        }

        return a;
    }

    if (!are_conn(a, b))
    {
        if (a.size() > b.size())
        {
            return a;
        }
        else
        {
            return b;
        }
    }

    if (a.size() < b.size())
        swap(a, b);

    assert(a.size() >= b.size());

    bool a_circle = are_conn({a.front()}, {a.back()});

    if (!a_circle)
    {
        for (int x : a)
            b.push_back(x);
        return b;
    }

    // a is a circle

    bool b_circle = b.size() == 1 || are_conn({b.front()}, {b.back()});

    if (!b_circle) {
        for (int x : b) a.push_back(x);
        return a;
    }

    // both a and b are circles
    // deque<int> A, B;
    // for (int x : a) A.push_back(x);
    // for (int x : b) B.push_back(x);

    // while (true) {
    //     int e = A.front(); A.pop_front();
    //     A.push_back(e);
    //     if (are_conn({e}, b)) break;
    // }

    // while (true) {
    //     int e = B.back(); B.pop_back();
    //     B.push_front(e);
    //     if (are_conn({A.back()}, {e})) break;
    // }

    // vector<int> res;
    // for (int x : A) res.push_back(x);
    // for (int x : B) res.push_back(x);
    // return res;

    // both a and b are circles
    // there is atleast one edge between a and b

    int a_connect;
    vector<int> x, y, A;

    for (int i: a) A.push_back(i);

    while (A.size() > 1) {
        x.clear();
        y.clear();
        for (int i = 0; i < A.size(); i++) {
            if (i % 2 == 0) x.push_back(A[i]);
            else y.push_back(A[i]);
        }

        if (are_conn(x, b)) { // the connection is in x
            A = x;
        } else {
            A = y;
        }
    }

    assert(A.size() == 1);
    a_connect = A[0];

    x.clear();
    y.clear();
    vector<int> B;
    int b_connect;

    for (int i: b) B.push_back(i);
    while (B.size() > 1) {
        x.clear();
        y.clear();
        for (int i = 0; i < B.size(); i++) {
            if (i % 2 == 0) x.push_back(B[i]);
            else y.push_back(B[i]);
        }

        if (are_conn({a_connect}, x)) { // the connection is in x
            B = x;
        } else {
            B = y;
        }
    }

    assert(B.size() == 1);
    b_connect = B[0];


    deque<int> A_d, B_d;
    for (int x : a) A_d.push_back(x);
    for (int x : b) B_d.push_back(x);

    while (true) {
        A_d.push_back(A_d.front());
        A_d.pop_front();
        if (A_d.back() == a_connect) break;
    }

    while (true) {
        B_d.push_front(B_d.back());
        B_d.pop_back();
        if (B_d.front() == b_connect) break;
    }

    vector<int> res;
    for (int x: A_d) res.push_back(x);
    for (int x: B_d) res.push_back(x);
    return res;
}

Compilation message

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:246:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  246 |         for (int i = 0; i < A.size(); i++) {
      |                         ~~^~~~~~~~~~
longesttrip.cpp:270:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  270 |         for (int i = 0; i < B.size(); i++) {
      |                         ~~^~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 2 ms 344 KB Output is correct

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 1 ms 344 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 344 KB Output is correct
2 Correct 8 ms 344 KB Output is correct
3 Correct 5 ms 344 KB Output is correct
4 Correct 5 ms 344 KB Output is correct
5 Correct 5 ms 344 KB Output is correct
6 Correct 5 ms 344 KB Output is correct
7 Correct 6 ms 344 KB Output is correct
8 Correct 5 ms 344 KB Output is correct
9 Correct 4 ms 344 KB Output is correct
10 Correct 5 ms 344 KB Output is correct
11 Correct 5 ms 344 KB Output is correct
12 Correct 5 ms 344 KB Output is correct
13 Correct 5 ms 344 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 344 KB Output is correct
2 Correct 8 ms 344 KB Output is correct
3 Correct 7 ms 344 KB Output is correct
4 Correct 6 ms 600 KB Output is correct
5 Correct 6 ms 344 KB Output is correct
6 Correct 9 ms 344 KB Output is correct
7 Correct 7 ms 344 KB Output is correct
8 Correct 6 ms 344 KB Output is correct
9 Correct 6 ms 344 KB Output is correct
10 Correct 7 ms 560 KB Output is correct
11 Correct 7 ms 344 KB Output is correct
12 Correct 6 ms 344 KB Output is correct
13 Correct 6 ms 344 KB Output is correct
14 Correct 8 ms 344 KB Output is correct
15 Correct 8 ms 344 KB Output is correct
16 Correct 11 ms 344 KB Output is correct
17 Correct 9 ms 600 KB Output is correct
18 Correct 8 ms 344 KB Output is correct
19 Correct 7 ms 492 KB Output is correct
20 Correct 7 ms 344 KB Output is correct
21 Correct 7 ms 344 KB Output is correct
22 Correct 7 ms 344 KB Output is correct
23 Correct 10 ms 652 KB Output is correct
24 Correct 10 ms 576 KB Output is correct
25 Correct 10 ms 344 KB Output is correct
26 Correct 12 ms 344 KB Output is correct
27 Correct 8 ms 344 KB Output is correct
28 Correct 8 ms 344 KB Output is correct
29 Correct 8 ms 600 KB Output is correct
30 Correct 6 ms 344 KB Output is correct
31 Correct 8 ms 344 KB Output is correct
32 Correct 9 ms 344 KB Output is correct
33 Correct 9 ms 344 KB Output is correct
34 Correct 7 ms 344 KB Output is correct
35 Correct 7 ms 344 KB Output is correct
36 Correct 7 ms 344 KB Output is correct
37 Correct 7 ms 600 KB Output is correct
38 Correct 9 ms 596 KB Output is correct
39 Correct 9 ms 636 KB Output is correct
40 Correct 10 ms 600 KB Output is correct
41 Correct 10 ms 600 KB Output is correct
42 Correct 12 ms 480 KB Output is correct
43 Correct 11 ms 604 KB Output is correct
44 Correct 10 ms 600 KB Output is correct
45 Correct 10 ms 344 KB Output is correct
46 Correct 11 ms 596 KB Output is correct
47 Correct 10 ms 344 KB Output is correct
48 Correct 10 ms 344 KB Output is correct
49 Correct 9 ms 344 KB Output is correct
50 Correct 8 ms 344 KB Output is correct
51 Correct 10 ms 344 KB Output is correct
52 Correct 11 ms 600 KB Output is correct
53 Correct 7 ms 344 KB Output is correct
54 Correct 8 ms 344 KB Output is correct
55 Correct 8 ms 344 KB Output is correct
56 Correct 8 ms 600 KB Output is correct
57 Correct 8 ms 600 KB Output is correct
58 Correct 9 ms 720 KB Output is correct
59 Correct 10 ms 600 KB Output is correct
60 Correct 16 ms 600 KB Output is correct
61 Correct 16 ms 676 KB Output is correct
62 Correct 11 ms 856 KB Output is correct
63 Correct 11 ms 600 KB Output is correct
64 Correct 13 ms 720 KB Output is correct

Subtask #4
45.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 344 KB Output is correct
2 Correct 8 ms 344 KB Output is correct
3 Correct 6 ms 344 KB Output is correct
4 Correct 6 ms 344 KB Output is correct
5 Correct 6 ms 344 KB Output is correct
6 Correct 9 ms 344 KB Output is correct
7 Correct 8 ms 344 KB Output is correct
8 Correct 6 ms 344 KB Output is correct
9 Correct 6 ms 476 KB Output is correct
10 Correct 9 ms 344 KB Output is correct
11 Correct 6 ms 344 KB Output is correct
12 Correct 7 ms 1368 KB Output is correct
13 Correct 6 ms 344 KB Output is correct
14 Correct 11 ms 344 KB Output is correct
15 Correct 8 ms 344 KB Output is correct
16 Correct 9 ms 344 KB Output is correct
17 Correct 9 ms 344 KB Output is correct
18 Correct 8 ms 600 KB Output is correct
19 Correct 9 ms 344 KB Output is correct
20 Correct 7 ms 488 KB Output is correct
21 Correct 9 ms 344 KB Output is correct
22 Correct 8 ms 344 KB Output is correct
23 Correct 8 ms 344 KB Output is correct
24 Correct 8 ms 344 KB Output is correct
25 Correct 7 ms 344 KB Output is correct
26 Correct 7 ms 344 KB Output is correct
27 Correct 9 ms 344 KB Output is correct
28 Correct 9 ms 344 KB Output is correct
29 Correct 9 ms 500 KB Output is correct
30 Correct 7 ms 344 KB Output is correct
31 Correct 7 ms 344 KB Output is correct
32 Correct 15 ms 344 KB Output is correct
33 Correct 10 ms 344 KB Output is correct
34 Correct 12 ms 344 KB Output is correct
35 Correct 11 ms 344 KB Output is correct
36 Correct 10 ms 344 KB Output is correct
37 Correct 7 ms 344 KB Output is correct
38 Correct 10 ms 344 KB Output is correct
39 Correct 11 ms 344 KB Output is correct
40 Correct 8 ms 344 KB Output is correct
41 Correct 8 ms 344 KB Output is correct
42 Correct 8 ms 344 KB Output is correct
43 Correct 7 ms 344 KB Output is correct
44 Correct 7 ms 600 KB Output is correct
45 Correct 7 ms 344 KB Output is correct
46 Correct 7 ms 600 KB Output is correct
47 Correct 8 ms 600 KB Output is correct
48 Correct 7 ms 600 KB Output is correct
49 Partially correct 9 ms 612 KB Output is partially correct
50 Partially correct 9 ms 600 KB Output is partially correct
51 Partially correct 15 ms 600 KB Output is partially correct
52 Correct 10 ms 600 KB Output is correct
53 Correct 10 ms 600 KB Output is correct
54 Correct 10 ms 600 KB Output is correct
55 Correct 10 ms 600 KB Output is correct
56 Correct 10 ms 600 KB Output is correct
57 Partially correct 9 ms 856 KB Output is partially correct
58 Partially correct 12 ms 624 KB Output is partially correct
59 Partially correct 12 ms 600 KB Output is partially correct
60 Correct 10 ms 596 KB Output is correct
61 Correct 11 ms 600 KB Output is correct
62 Correct 9 ms 600 KB Output is correct
63 Correct 8 ms 600 KB Output is correct
64 Partially correct 13 ms 752 KB Output is partially correct
65 Correct 14 ms 600 KB Output is correct
66 Partially correct 16 ms 600 KB Output is partially correct
67 Correct 16 ms 600 KB Output is correct
68 Correct 16 ms 760 KB Output is correct
69 Partially correct 11 ms 600 KB Output is partially correct
70 Partially correct 11 ms 616 KB Output is partially correct
71 Correct 8 ms 600 KB Output is correct
72 Correct 9 ms 600 KB Output is correct
73 Correct 10 ms 600 KB Output is correct
74 Partially correct 14 ms 600 KB Output is partially correct
75 Correct 12 ms 728 KB Output is correct
76 Correct 11 ms 600 KB Output is correct
77 Correct 7 ms 600 KB Output is correct
78 Correct 10 ms 624 KB Output is correct
79 Correct 10 ms 600 KB Output is correct
80 Partially correct 12 ms 600 KB Output is partially correct
81 Correct 11 ms 600 KB Output is correct
82 Correct 14 ms 916 KB Output is correct