oj.uz

Submission #628808

# Submission time Handle Problem Language Result Execution time Memory
628808 2022-08-13T17:25:36 Z dqhungdl Thousands Islands (IOI22_islands) C++17
55 / 100
 81 ms 33488 KB 
#include "islands.h"
#include <bits/stdc++.h>
#include <variant>
using namespace std;

const int MAX = 1e5 + 5;
typedef pair<int, int> ii;
int N, mark[MAX];
vector<vector<vector<int>>> g;
vector<ii> ng[MAX];
vector<int> path;

bool dfs(int u) {
    if (mark[u] == 2)
        return false;
    if (mark[u] == 1) {
        path.push_back(u);
        return true;
    }
    mark[u] = 1;
    for (auto &[v, id]: ng[u])
        if (dfs(v)) {
            path.push_back(u);
            return true;
        }
    mark[u] = 2;
    return false;
}

bool dfs1(int u) {
    if ((!u && ng[u].size() >= 2) || ng[u].size() >= 3) {
        path.push_back(u);
        return true;
    }
    if (mark[u])
        return false;
    mark[u] = true;
    for (auto &[v, id]: ng[u])
        if (dfs1(v)) {
            path.push_back(u);
            return true;
        }
    return false;
}

variant<bool, vector<int>> find_journey(int _N, int M, vector<int> U, vector<int> V) {
    N = _N;
    if (N == 2) {
        vector<int> g[2];
        for (int i = 0; i < M; i++)
            g[U[i]].push_back(i);
        if (g[0].size() < 2 || g[1].empty())
            return false;
        return vector<int>({g[0][0], g[1][0], g[0][1], g[0][0], g[1][0], g[0][1]});
    }

    g.resize(N, vector<vector<int>>(N));
    for (int i = 0; i < M; i++)
        g[U[i]][V[i]].push_back(i);
    bool isClique = true;
    for (int i = 0; i < N && isClique; i++)
        for (int j = 0; j < N && isClique; j++)
            if (i != j && g[i][j].empty())
                isClique = false;
    if (isClique)
        return vector<int>({g[0][1][0], g[1][2][0], g[2][0][0], g[0][2][0], g[2][1][0], g[1][0][0],
                            g[2][0][0], g[1][2][0], g[0][1][0], g[1][0][0], g[2][1][0], g[0][2][0]});

    bool isDoubled = M % 2 == 0;
    for (int i = 1; i < M && isDoubled; i += 2)
        if (U[i - 1] != U[i] || V[i - 1] != V[i])
            isDoubled = false;
    if (isDoubled) {
        for (int i = 1; i < M; i += 2)
            ng[U[i]].emplace_back(V[i], i);
        if (dfs(0)) {
            reverse(path.begin(), path.end());
            int pivot = -1;
            for (int i = 0; i < path.size(); i++)
                if (path[i] == path.back()) {
                    pivot = i;
                    break;
                }
            vector<int> rs;
            for (int i = 0; i < pivot; i++)
                rs.push_back(g[path[i]][path[i + 1]][0]);
            for (int i = pivot; i < path.size() - 1; i++)
                rs.push_back(g[path[i]][path[i + 1]][0]);
            for (int i = pivot; i < path.size() - 1; i++)
                rs.push_back(g[path[i]][path[i + 1]][1]);
            for (int i = path.size() - 2; i >= pivot; i--)
                rs.push_back(g[path[i]][path[i + 1]][0]);
            for (int i = path.size() - 2; i >= pivot; i--)
                rs.push_back(g[path[i]][path[i + 1]][1]);
            for (int i = pivot - 1; i >= 0; i--)
                rs.push_back(g[path[i]][path[i + 1]][0]);
            return rs;
        }
        return false;
    }
    for (int i = 0; i < M; i++)
        ng[U[i]].emplace_back(V[i], i);
    if (dfs1(0)) {
        reverse(path.begin(), path.end());
        vector<int> rs;
        for (int i = 0; i < path.size() - 1; i++)
            rs.push_back(g[path[i]][path[i + 1]][0]);
        int p = path.size() == 1 ? -1 : path[path.size() - 2];
        vector<int> sample;
        for (auto &[v, id]: ng[path.back()])
            if (v != p) {
                sample.push_back(id);
                if (sample.size() == 2)
                    break;
            }
        for (int id: sample) {
            rs.push_back(id);
            rs.push_back(id % 2 ? id - 1 : id + 1);
        }
        for (int id: sample) {
            rs.push_back(id % 2 ? id - 1 : id + 1);
            rs.push_back(id);
        }
        for (int i = (int) path.size() - 2; i >= 0; i--)
            rs.push_back(g[path[i]][path[i + 1]][0]);
        return rs;
    }
    return false;
}

//int main() {
//    freopen("../_input", "r", stdin);
//    int N, M;
//    assert(2 == scanf("%d %d", &N, &M));
//
//    vector<int> U(M), V(M);
//    for (int i = 0; i < M; ++i) {
//        assert(2 == scanf("%d %d", &U[i], &V[i]));
//    }
//
//    variant<bool, vector<int>> result = find_journey(N, M, U, V);
//    if (result.index() == 0) {
//        printf("0\n");
//        if (get<bool>(result)) {
//            printf("1\n");
//        } else {
//            printf("0\n");
//        }
//    } else {
//        printf("1\n");
//        vector<int> &canoes = get<vector<int>>(result);
//        printf("%d\n", static_cast<int>(canoes.size()));
//        for (int i = 0; i < static_cast<int>(canoes.size()); ++i) {
//            if (i > 0) {
//                printf(" ");
//            }
//            printf("%d", canoes[i]);
//        }
//        printf("\n");
//    }
//    return 0;
//}

Compilation message

islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > find_journey(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:79:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |             for (int i = 0; i < path.size(); i++)
      |                             ~~^~~~~~~~~~~~~
islands.cpp:87:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |             for (int i = pivot; i < path.size() - 1; i++)
      |                                 ~~^~~~~~~~~~~~~~~~~
islands.cpp:89:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |             for (int i = pivot; i < path.size() - 1; i++)
      |                                 ~~^~~~~~~~~~~~~~~~~
islands.cpp:106:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |         for (int i = 0; i < path.size() - 1; i++)
      |                         ~~^~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 37 ms 6780 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 59 ms 13876 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 26324 KB Output is correct
2 Correct 2 ms 2900 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 16 ms 26324 KB Output is correct
6 Correct 1 ms 2536 KB Output is correct
7 Correct 18 ms 26196 KB Output is correct
8 Correct 2 ms 2900 KB Output is correct
9 Correct 2 ms 2900 KB Output is correct
10 Correct 18 ms 26304 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 17 ms 26324 KB Output is correct
13 Correct 1 ms 2772 KB Output is correct
14 Correct 2 ms 2772 KB Output is correct
15 Correct 2 ms 2900 KB Output is correct
16 Correct 2 ms 2900 KB Output is correct
17 Correct 55 ms 31808 KB Output is correct
18 Correct 58 ms 30932 KB Output is correct
19 Correct 2 ms 2644 KB Output is correct
20 Correct 2 ms 2644 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 50 ms 13884 KB Output is correct

Subtask #4
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2900 KB Output is correct
2 Correct 2 ms 3028 KB Output is correct
3 Correct 41 ms 7908 KB Output is correct
4 Correct 65 ms 32344 KB Output is correct
5 Correct 14 ms 21820 KB Output is correct
6 Correct 14 ms 21844 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 18 ms 26336 KB Output is correct
11 Correct 17 ms 26284 KB Output is correct
12 Correct 17 ms 26324 KB Output is correct
13 Correct 17 ms 26324 KB Output is correct
14 Correct 20 ms 26324 KB Output is correct
15 Correct 17 ms 26420 KB Output is correct
16 Correct 17 ms 26196 KB Output is correct
17 Correct 2 ms 2644 KB Output is correct
18 Correct 17 ms 26332 KB Output is correct
19 Correct 19 ms 26160 KB Output is correct
20 Correct 42 ms 8448 KB Output is correct
21 Correct 67 ms 32564 KB Output is correct
22 Correct 16 ms 26236 KB Output is correct
23 Correct 16 ms 26196 KB Output is correct
24 Correct 1 ms 2900 KB Output is correct
25 Correct 2 ms 2900 KB Output is correct
26 Correct 18 ms 26284 KB Output is correct
27 Correct 81 ms 32332 KB Output is correct
28 Correct 68 ms 32480 KB Output is correct
29 Correct 1 ms 2772 KB Output is correct
30 Correct 75 ms 33488 KB Output is correct
31 Correct 2 ms 2644 KB Output is correct
32 Correct 68 ms 32564 KB Output is correct
33 Correct 41 ms 8268 KB Output is correct
34 Correct 43 ms 29808 KB Output is correct
35 Correct 7 ms 9940 KB Output is correct
36 Correct 59 ms 31692 KB Output is correct
37 Correct 70 ms 33156 KB Output is correct
38 Correct 6 ms 8532 KB Output is correct
39 Correct 51 ms 13972 KB Output is correct
40 Correct 16 ms 26228 KB Output is correct
41 Correct 74 ms 33452 KB Output is correct
42 Correct 67 ms 32572 KB Output is correct
43 Correct 2 ms 2900 KB Output is correct
44 Correct 18 ms 26324 KB Output is correct
45 Correct 17 ms 26348 KB Output is correct
46 Correct 44 ms 29220 KB Output is correct

Subtask #5
0.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 37 ms 6780 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 59 ms 13876 KB Output is correct
14 Correct 17 ms 26324 KB Output is correct
15 Correct 2 ms 2900 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Correct 16 ms 26324 KB Output is correct
19 Correct 1 ms 2536 KB Output is correct
20 Correct 18 ms 26196 KB Output is correct
21 Correct 2 ms 2900 KB Output is correct
22 Correct 2 ms 2900 KB Output is correct
23 Correct 18 ms 26304 KB Output is correct
24 Correct 1 ms 2644 KB Output is correct
25 Correct 17 ms 26324 KB Output is correct
26 Correct 1 ms 2772 KB Output is correct
27 Correct 2 ms 2772 KB Output is correct
28 Correct 2 ms 2900 KB Output is correct
29 Correct 2 ms 2900 KB Output is correct
30 Correct 55 ms 31808 KB Output is correct
31 Correct 58 ms 30932 KB Output is correct
32 Correct 2 ms 2644 KB Output is correct
33 Correct 2 ms 2644 KB Output is correct
34 Correct 2 ms 2644 KB Output is correct
35 Correct 2 ms 2644 KB Output is correct
36 Correct 50 ms 13884 KB Output is correct
37 Partially correct 2 ms 2644 KB Output is partially correct
38 Correct 1 ms 2644 KB Output is correct
39 Incorrect 2 ms 2900 KB Output isn't correct
40 Halted 0 ms 0 KB -