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Submission #841327

# Submission time Handle Problem Language Result Execution time Memory
841327 2023-09-01T13:54:15 Z I_love_Hoang_Yen Longest Trip (IOI23_longesttrip) C++17
100 / 100
 16 ms 436 KB 
#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;

// Subtask 1: D == 3
vector<int> sub1(int n) {
    vector<int> res(n);
    std::iota(res.begin(), res.end(), 0);
    return res;
}

// Subtask 2: D == 2
bool has_edge(int u, int v) {
    return are_connected({u}, {v});
}

vector<int> sub2(int n) {
    vector<int> res {0};
    for (int i = 1; i < n; i++) {
        if (has_edge(0, i)) {
            res.push_back(i);
            break;
        }
    }

    for (int i = 1; i < n; i++) {
        if (i == res[1]) continue;

        if (has_edge(res.back(), i)) {
            res.push_back(i);
        } else {
            res.insert(res.begin(), i);
        }
    }

    return res;
}

// Subtask 3: D == 1, return path with length >= Lmax / 2
vector<int> sub3(int n) {
    // maintain 2 paths
    vector<int> p1 {0}, p2 {1};

    for (int i = 2; i < n; ++i) {
        // consider p1.back(), p2.back(), i
        // -> there's at least 1 edge

        if (has_edge(p1.back(), i)) {
            p1.push_back(i);
        } else if (has_edge(p2.back(), i)) {
            p2.push_back(i);
        } else {
            reverse(p2.begin(), p2.end());
            p1.insert(p1.end(), p2.begin(), p2.end());
            p2 = {i};
        }
    }
    if (p1.size() > p2.size()) return p1;
    return p2;
}

// Subtask 4: D == 1
vector<int> sub4(int n) {
    // Use subtask 3 to get 2 paths {{{
    vector<int> p1 {0}, p2 {1};
    bool last_to_2 = false;
    for (int i = 2; i < n; ++i) {
        if (has_edge(p1.back(), i)) {
            p1.push_back(i);
            last_to_2 = false;
        } else if (last_to_2 || has_edge(p2.back(), i)) {
            p2.push_back(i);
            last_to_2 = true;
        } else {
            reverse(p2.begin(), p2.end());
            p1.insert(p1.end(), p2.begin(), p2.end());
            p2 = {i};
            last_to_2 = false;
        }
    }
    // }}}
    
    // Make p1 longer path
    if (p1.size() < p2.size()) swap(p1, p2);
    if (p2.empty()) return p1;

    // Impossible to merge 2 paths
    if (!are_connected(p1, p2)) {
        return p1;
    }
    
    // Merge 2 paths:
    // Consider: p1[0], p1.back() and p2[0] -> at least 1 edge
    if (has_edge(p1.back(), p2[0])) {
        p1.insert(p1.end(), p2.begin(), p2.end());
        return p1;
    } else if (has_edge(p1[0], p2[0])) {
        reverse(p2.begin(), p2.end());
        p2.insert(p2.end(), p1.begin(), p1.end());
        return p2;
    }

    // p1 is now a circle
    // Consider: p2[0], p2.back() and p1[0] -> at least 1 edge
    if (p2.size() > 1) {
        if (has_edge(p2[0], p1[0])) {
            reverse(p1.begin(), p1.end());
            p1.insert(p1.end(), p2.begin(), p2.end());
            return p1;
        } else if (has_edge(p2.back(), p1[0])) {
            p2.insert(p2.end(), p1.begin(), p1.end());
            return p2;
        }
    }

    // p2 is now also a circle
    // Find one edge from p1 -> p2
    int l1 = 0, r1 = p1.size() - 1;  // p1[l1..r1] has at least one edge to p2
    while (l1 < r1) {
        int mid = (l1 + r1) / 2;
        if (are_connected(vector<int>(p1.begin() + l1, p1.begin() + mid + 1), p2)) {
            r1 = mid;
        } else l1 = mid + 1;
    }
    int l2 = 0, r2 = p2.size() - 1;  // p2[l2..r2] has at least one edge to p1[l1]
    while (l2 < r2) {
        int mid = (l2 + r2) / 2;
        if (are_connected({p1[l1]}, vector<int>(p2.begin() + l2, p2.begin() + mid + 1))) {
            r2 = mid;
        } else l2 = mid + 1;
    }

    vector<int> res;
    res.insert(res.end(), p1.begin() + l1 + 1, p1.end());
    res.insert(res.end(), p1.begin(), p1.begin() + l1 + 1);
    res.insert(res.end(), p2.begin() + l2, p2.end());
    res.insert(res.end(), p2.begin(), p2.begin() + l2);
    return res;
}

vector<int> longest_trip(int n, int d) {
    if (d == 3) return sub1(n);
    if (d == 2) return sub2(n);
    return sub4(n);
}

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 208 KB Output is correct
2 Correct 4 ms 244 KB Output is correct

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 208 KB Output is correct
2 Correct 1 ms 208 KB Output is correct
3 Correct 1 ms 208 KB Output is correct
4 Correct 1 ms 208 KB Output is correct
5 Correct 0 ms 208 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 208 KB Output is correct
2 Correct 8 ms 208 KB Output is correct
3 Correct 10 ms 208 KB Output is correct
4 Correct 10 ms 208 KB Output is correct
5 Correct 12 ms 208 KB Output is correct
6 Correct 13 ms 208 KB Output is correct
7 Correct 10 ms 256 KB Output is correct
8 Correct 9 ms 256 KB Output is correct
9 Correct 8 ms 208 KB Output is correct
10 Correct 15 ms 208 KB Output is correct
11 Correct 7 ms 208 KB Output is correct
12 Correct 7 ms 208 KB Output is correct
13 Correct 7 ms 208 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 208 KB Output is correct
2 Correct 7 ms 208 KB Output is correct
3 Correct 8 ms 208 KB Output is correct
4 Correct 8 ms 208 KB Output is correct
5 Correct 7 ms 208 KB Output is correct
6 Correct 11 ms 208 KB Output is correct
7 Correct 11 ms 208 KB Output is correct
8 Correct 7 ms 208 KB Output is correct
9 Correct 9 ms 208 KB Output is correct
10 Correct 10 ms 208 KB Output is correct
11 Correct 7 ms 208 KB Output is correct
12 Correct 9 ms 208 KB Output is correct
13 Correct 9 ms 296 KB Output is correct
14 Correct 7 ms 208 KB Output is correct
15 Correct 8 ms 208 KB Output is correct
16 Correct 12 ms 208 KB Output is correct
17 Correct 12 ms 208 KB Output is correct
18 Correct 7 ms 208 KB Output is correct
19 Correct 10 ms 288 KB Output is correct
20 Correct 8 ms 208 KB Output is correct
21 Correct 7 ms 208 KB Output is correct
22 Correct 9 ms 436 KB Output is correct
23 Correct 7 ms 208 KB Output is correct
24 Correct 11 ms 208 KB Output is correct
25 Correct 12 ms 208 KB Output is correct
26 Correct 11 ms 208 KB Output is correct
27 Correct 11 ms 208 KB Output is correct
28 Correct 9 ms 208 KB Output is correct
29 Correct 11 ms 208 KB Output is correct
30 Correct 8 ms 208 KB Output is correct
31 Correct 10 ms 208 KB Output is correct
32 Correct 11 ms 208 KB Output is correct
33 Correct 5 ms 208 KB Output is correct
34 Correct 9 ms 208 KB Output is correct
35 Correct 7 ms 208 KB Output is correct
36 Correct 7 ms 208 KB Output is correct
37 Correct 10 ms 208 KB Output is correct
38 Correct 8 ms 208 KB Output is correct
39 Correct 7 ms 208 KB Output is correct
40 Correct 7 ms 332 KB Output is correct
41 Correct 11 ms 208 KB Output is correct
42 Correct 11 ms 208 KB Output is correct
43 Correct 8 ms 208 KB Output is correct
44 Correct 8 ms 208 KB Output is correct
45 Correct 10 ms 208 KB Output is correct
46 Correct 15 ms 208 KB Output is correct
47 Correct 11 ms 208 KB Output is correct
48 Correct 10 ms 208 KB Output is correct
49 Correct 13 ms 208 KB Output is correct
50 Correct 10 ms 208 KB Output is correct
51 Correct 11 ms 208 KB Output is correct
52 Correct 12 ms 208 KB Output is correct
53 Correct 8 ms 208 KB Output is correct
54 Correct 8 ms 208 KB Output is correct
55 Correct 11 ms 256 KB Output is correct
56 Correct 7 ms 208 KB Output is correct
57 Correct 7 ms 304 KB Output is correct
58 Correct 8 ms 208 KB Output is correct
59 Correct 12 ms 208 KB Output is correct
60 Correct 9 ms 208 KB Output is correct
61 Correct 11 ms 300 KB Output is correct
62 Correct 8 ms 208 KB Output is correct
63 Correct 11 ms 208 KB Output is correct
64 Correct 9 ms 300 KB Output is correct

Subtask #4
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 208 KB Output is correct
2 Correct 11 ms 208 KB Output is correct
3 Correct 8 ms 208 KB Output is correct
4 Correct 8 ms 208 KB Output is correct
5 Correct 7 ms 208 KB Output is correct
6 Correct 10 ms 208 KB Output is correct
7 Correct 7 ms 208 KB Output is correct
8 Correct 10 ms 208 KB Output is correct
9 Correct 6 ms 300 KB Output is correct
10 Correct 8 ms 208 KB Output is correct
11 Correct 7 ms 208 KB Output is correct
12 Correct 8 ms 208 KB Output is correct
13 Correct 10 ms 208 KB Output is correct
14 Correct 11 ms 208 KB Output is correct
15 Correct 9 ms 208 KB Output is correct
16 Correct 13 ms 208 KB Output is correct
17 Correct 7 ms 208 KB Output is correct
18 Correct 8 ms 336 KB Output is correct
19 Correct 5 ms 332 KB Output is correct
20 Correct 5 ms 208 KB Output is correct
21 Correct 9 ms 208 KB Output is correct
22 Correct 12 ms 208 KB Output is correct
23 Correct 12 ms 208 KB Output is correct
24 Correct 10 ms 208 KB Output is correct
25 Correct 10 ms 208 KB Output is correct
26 Correct 9 ms 208 KB Output is correct
27 Correct 10 ms 208 KB Output is correct
28 Correct 10 ms 208 KB Output is correct
29 Correct 10 ms 208 KB Output is correct
30 Correct 10 ms 208 KB Output is correct
31 Correct 5 ms 208 KB Output is correct
32 Correct 9 ms 208 KB Output is correct
33 Correct 16 ms 208 KB Output is correct
34 Correct 13 ms 208 KB Output is correct
35 Correct 15 ms 208 KB Output is correct
36 Correct 10 ms 208 KB Output is correct
37 Correct 10 ms 208 KB Output is correct
38 Correct 13 ms 300 KB Output is correct
39 Correct 9 ms 208 KB Output is correct
40 Correct 9 ms 208 KB Output is correct
41 Correct 8 ms 208 KB Output is correct
42 Correct 12 ms 208 KB Output is correct
43 Correct 8 ms 328 KB Output is correct
44 Correct 8 ms 208 KB Output is correct
45 Correct 8 ms 208 KB Output is correct
46 Correct 10 ms 208 KB Output is correct
47 Correct 9 ms 208 KB Output is correct
48 Correct 6 ms 208 KB Output is correct
49 Correct 11 ms 208 KB Output is correct
50 Correct 8 ms 332 KB Output is correct
51 Correct 8 ms 208 KB Output is correct
52 Correct 12 ms 208 KB Output is correct
53 Correct 8 ms 208 KB Output is correct
54 Correct 12 ms 208 KB Output is correct
55 Correct 8 ms 208 KB Output is correct
56 Correct 10 ms 208 KB Output is correct
57 Correct 8 ms 208 KB Output is correct
58 Correct 10 ms 208 KB Output is correct
59 Correct 11 ms 208 KB Output is correct
60 Correct 9 ms 208 KB Output is correct
61 Correct 8 ms 208 KB Output is correct
62 Correct 9 ms 208 KB Output is correct
63 Correct 10 ms 208 KB Output is correct
64 Correct 14 ms 208 KB Output is correct
65 Correct 8 ms 208 KB Output is correct
66 Correct 9 ms 208 KB Output is correct
67 Correct 9 ms 208 KB Output is correct
68 Correct 13 ms 284 KB Output is correct
69 Correct 13 ms 208 KB Output is correct
70 Correct 10 ms 208 KB Output is correct
71 Correct 10 ms 208 KB Output is correct
72 Correct 7 ms 208 KB Output is correct
73 Correct 12 ms 208 KB Output is correct
74 Correct 10 ms 208 KB Output is correct
75 Correct 9 ms 320 KB Output is correct
76 Correct 13 ms 208 KB Output is correct
77 Correct 10 ms 208 KB Output is correct
78 Correct 11 ms 208 KB Output is correct
79 Correct 12 ms 208 KB Output is correct
80 Correct 7 ms 208 KB Output is correct
81 Correct 8 ms 208 KB Output is correct
82 Correct 9 ms 208 KB Output is correct