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Submission #628648

# Submission time Handle Problem Language Result Execution time Memory
628648 2022-08-13T14:48:14 Z qwerasdfzxcl Thousands Islands (IOI22_islands) C++17
100 / 100
 336 ms 38536 KB 
#include "islands.h"
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
pair<int, int> E[200200];
set<pair<int, int>> adj[100100], INV[100100];
vector<int> deg0, ansf, ansb;
int n, s, on[100100], visited[100100], cyc[200200];
bool flag = 0;

vector<int> operator + (const vector<int> &a, const vector<int> &b){
    vector<int> ret = a;
    for (auto &x:b) ret.push_back(x);
    return ret;
}

vector<int> rev(vector<int> a){reverse(a.begin(), a.end()); return a;}

void pop(int x){
    auto [v, i] = *adj[x].begin();
    adj[x].erase(adj[x].begin());
    INV[v].erase(INV[v].find(make_pair(x, i)));
}

void _erase(int x){
    if (!on[x]) return;
    on[x] = 0;
    for (auto &[v, i]:INV[x]){
        adj[v].erase(adj[v].find(make_pair(x, i)));
        if (adj[v].empty()) deg0.push_back(v);
    }
    for (auto &[v, i]:adj[x]) INV[v].erase(INV[v].find(make_pair(x, i)));
}

void flip(int i){
    auto [u, v] = E[i];
    adj[u].erase(adj[u].find(make_pair(v, i))); INV[u].emplace(v, i);
    INV[v].erase(INV[v].find(make_pair(u, i))); adj[v].emplace(u, i);
    swap(E[i].first, E[i].second);
}

pair<vector<int>, vector<int>> solve(int is, int typ){
    int cur = E[is].second;
    vector<int> ret1 = {is};
    if (!visited[s]) visited[s] = typ;

    while(!visited[cur]){
        visited[cur] = typ;
        ret1.push_back(adj[cur].begin()->second);
        cur = adj[cur].begin()->first;
    }

    if (visited[cur]!=typ){ ///use same cycle
        flag = 1;
        vector<int> ret2;
        while(visited[cur]!=typ){
            visited[cur] = typ;
            if (!cyc[adj[cur].begin()->second]){
                assert(cur==s);
                ret2.push_back(adj[cur].rbegin()->second);
                cur = adj[cur].rbegin()->first;
                continue;
            }
            ret2.push_back(adj[cur].begin()->second);
            cur = adj[cur].begin()->first;
        }
        return {ret1, ret2};
    }

    int tmp = cur==s?is:adj[cur].begin()->second;
    auto iter = find(ret1.begin(), ret1.end(), tmp);
    vector<int> ret2(iter, ret1.end());
    ret1.erase(iter, ret1.end());

    for (auto &x:ret1) visited[E[x].first] = 0;
    for (auto &x:ret2) {flip(x); cyc[x] = 1;}
    return {ret1, ret2};
}

std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {

    n = N, s = 1;
    fill(on+1, on+n+1, 1);
    for (int i=0;i<M;i++){
        ++U[i], ++V[i];
        adj[U[i]].emplace(V[i], i);
        INV[V[i]].emplace(U[i], i);
        E[i] = {U[i], V[i]};
    }

    for (int i=1;i<=n;i++) if (adj[i].empty()) deg0.push_back(i);
    while(true){
        while(!deg0.empty()){
            int x = deg0.back(); deg0.pop_back();
            _erase(x);
        }
        if (!on[s]) return false;
        if (adj[s].size()>1) break;

        ansf.push_back(adj[s].begin()->second);
        ansb.push_back(adj[s].begin()->second);
        int nxt = adj[s].begin()->first;
        _erase(s);
        s = nxt;
    }

    for (int i=1;i<=n;i++) if (on[i]){
        int sz = (i==s)?2:1;
        while((int)adj[i].size()>sz) pop(i);
    }

    int i1 = adj[s].begin()->second, i2 = adj[s].rbegin()->second;
    auto [p1, c1] = solve(i1, 1);
    auto [p2, c2] = solve(i2, 2);

    /*printf("flag = %d\n", flag);
    for (auto &x:p1) printf("%d ", x);
    printf("\n");
    for (auto &x:c1) printf("%d ", x);
    printf("\n");
    for (auto &x:p2) printf("%d ", x);
    printf("\n");
    for (auto &x:c2) printf("%d ", x);
    printf("\n");*/

    if (flag) return ansf + p1 + c1 + rev(p1) + p2 + c2 + rev(p2) + rev(ansb);

    return ansf + p1 + c1 + rev(p1) + p2 + c2 + rev(p2) + p1 + rev(c1) + rev(p1) + p2 + rev(c2) + rev(p2) + rev(ansb);
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 5 ms 9668 KB Output is correct
3 Correct 5 ms 9684 KB Output is correct
4 Correct 5 ms 9600 KB Output is correct
5 Correct 4 ms 9684 KB Output is correct
6 Correct 5 ms 9684 KB Output is correct
7 Correct 128 ms 33168 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 7 ms 9684 KB Output is correct
3 Correct 6 ms 9620 KB Output is correct
4 Correct 6 ms 9708 KB Output is correct
5 Correct 5 ms 9724 KB Output is correct
6 Correct 186 ms 28408 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 10196 KB Output is correct
2 Correct 5 ms 9748 KB Output is correct
3 Correct 5 ms 9684 KB Output is correct
4 Correct 5 ms 9684 KB Output is correct
5 Correct 8 ms 9940 KB Output is correct
6 Correct 7 ms 9684 KB Output is correct
7 Correct 5 ms 9812 KB Output is correct
8 Correct 5 ms 9684 KB Output is correct
9 Correct 5 ms 9684 KB Output is correct
10 Correct 7 ms 9940 KB Output is correct
11 Correct 6 ms 9684 KB Output is correct
12 Correct 6 ms 9940 KB Output is correct
13 Correct 7 ms 9684 KB Output is correct
14 Correct 5 ms 9684 KB Output is correct
15 Correct 5 ms 9684 KB Output is correct
16 Correct 7 ms 9684 KB Output is correct
17 Correct 105 ms 21376 KB Output is correct
18 Correct 67 ms 19120 KB Output is correct
19 Correct 5 ms 9684 KB Output is correct
20 Correct 5 ms 9660 KB Output is correct
21 Correct 8 ms 9648 KB Output is correct
22 Correct 5 ms 9684 KB Output is correct
23 Correct 170 ms 28440 KB Output is correct

Subtask #4
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 9684 KB Output is correct
2 Correct 8 ms 10128 KB Output is correct
3 Correct 196 ms 30800 KB Output is correct
4 Correct 186 ms 30968 KB Output is correct
5 Correct 8 ms 10068 KB Output is correct
6 Correct 7 ms 10128 KB Output is correct
7 Correct 6 ms 9604 KB Output is correct
8 Correct 7 ms 9684 KB Output is correct
9 Correct 5 ms 9684 KB Output is correct
10 Correct 7 ms 10068 KB Output is correct
11 Correct 7 ms 10068 KB Output is correct
12 Correct 9 ms 10184 KB Output is correct
13 Correct 7 ms 10196 KB Output is correct
14 Correct 10 ms 10196 KB Output is correct
15 Correct 11 ms 10324 KB Output is correct
16 Correct 7 ms 9940 KB Output is correct
17 Correct 5 ms 9684 KB Output is correct
18 Correct 7 ms 10212 KB Output is correct
19 Correct 14 ms 9940 KB Output is correct
20 Correct 209 ms 33120 KB Output is correct
21 Correct 276 ms 30828 KB Output is correct
22 Correct 7 ms 9940 KB Output is correct
23 Correct 6 ms 9812 KB Output is correct
24 Correct 8 ms 9632 KB Output is correct
25 Correct 7 ms 9940 KB Output is correct
26 Correct 7 ms 9940 KB Output is correct
27 Correct 240 ms 32388 KB Output is correct
28 Correct 230 ms 32056 KB Output is correct
29 Correct 5 ms 9684 KB Output is correct
30 Correct 222 ms 33164 KB Output is correct
31 Correct 5 ms 9684 KB Output is correct
32 Correct 222 ms 30852 KB Output is correct
33 Correct 204 ms 32024 KB Output is correct
34 Correct 89 ms 21428 KB Output is correct
35 Correct 9 ms 9832 KB Output is correct
36 Correct 187 ms 28484 KB Output is correct
37 Correct 254 ms 32028 KB Output is correct
38 Correct 7 ms 9940 KB Output is correct
39 Correct 201 ms 27704 KB Output is correct
40 Correct 9 ms 10080 KB Output is correct
41 Correct 259 ms 33180 KB Output is correct
42 Correct 253 ms 32072 KB Output is correct
43 Correct 6 ms 9684 KB Output is correct
44 Correct 7 ms 10196 KB Output is correct
45 Correct 6 ms 9940 KB Output is correct
46 Correct 63 ms 19120 KB Output is correct

Subtask #5
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 5 ms 9668 KB Output is correct
3 Correct 5 ms 9684 KB Output is correct
4 Correct 5 ms 9600 KB Output is correct
5 Correct 4 ms 9684 KB Output is correct
6 Correct 5 ms 9684 KB Output is correct
7 Correct 128 ms 33168 KB Output is correct
8 Correct 5 ms 9684 KB Output is correct
9 Correct 7 ms 9684 KB Output is correct
10 Correct 6 ms 9620 KB Output is correct
11 Correct 6 ms 9708 KB Output is correct
12 Correct 5 ms 9724 KB Output is correct
13 Correct 186 ms 28408 KB Output is correct
14 Correct 9 ms 10196 KB Output is correct
15 Correct 5 ms 9748 KB Output is correct
16 Correct 5 ms 9684 KB Output is correct
17 Correct 5 ms 9684 KB Output is correct
18 Correct 8 ms 9940 KB Output is correct
19 Correct 7 ms 9684 KB Output is correct
20 Correct 5 ms 9812 KB Output is correct
21 Correct 5 ms 9684 KB Output is correct
22 Correct 5 ms 9684 KB Output is correct
23 Correct 7 ms 9940 KB Output is correct
24 Correct 6 ms 9684 KB Output is correct
25 Correct 6 ms 9940 KB Output is correct
26 Correct 7 ms 9684 KB Output is correct
27 Correct 5 ms 9684 KB Output is correct
28 Correct 5 ms 9684 KB Output is correct
29 Correct 7 ms 9684 KB Output is correct
30 Correct 105 ms 21376 KB Output is correct
31 Correct 67 ms 19120 KB Output is correct
32 Correct 5 ms 9684 KB Output is correct
33 Correct 5 ms 9660 KB Output is correct
34 Correct 8 ms 9648 KB Output is correct
35 Correct 5 ms 9684 KB Output is correct
36 Correct 170 ms 28440 KB Output is correct
37 Correct 6 ms 9684 KB Output is correct
38 Correct 5 ms 9684 KB Output is correct
39 Correct 6 ms 9684 KB Output is correct
40 Correct 6 ms 9812 KB Output is correct
41 Correct 113 ms 20284 KB Output is correct
42 Correct 8 ms 10300 KB Output is correct
43 Correct 132 ms 21648 KB Output is correct
44 Correct 128 ms 21656 KB Output is correct
45 Correct 120 ms 21612 KB Output is correct
46 Correct 5 ms 9684 KB Output is correct
47 Correct 5 ms 9728 KB Output is correct
48 Correct 6 ms 9684 KB Output is correct
49 Correct 6 ms 9940 KB Output is correct
50 Correct 161 ms 30248 KB Output is correct
51 Correct 289 ms 33484 KB Output is correct
52 Correct 291 ms 33580 KB Output is correct
53 Correct 323 ms 34080 KB Output is correct
54 Correct 292 ms 33584 KB Output is correct
55 Correct 265 ms 33500 KB Output is correct
56 Correct 273 ms 33700 KB Output is correct
57 Correct 213 ms 32880 KB Output is correct
58 Correct 130 ms 33604 KB Output is correct
59 Correct 228 ms 33952 KB Output is correct
60 Correct 260 ms 33952 KB Output is correct
61 Correct 232 ms 33772 KB Output is correct
62 Correct 23 ms 13780 KB Output is correct
63 Correct 174 ms 32464 KB Output is correct
64 Correct 121 ms 21964 KB Output is correct
65 Correct 5 ms 9664 KB Output is correct
66 Correct 6 ms 9812 KB Output is correct
67 Correct 210 ms 34312 KB Output is correct
68 Correct 336 ms 33268 KB Output is correct
69 Correct 108 ms 22144 KB Output is correct
70 Correct 6 ms 9940 KB Output is correct
71 Correct 175 ms 27592 KB Output is correct
72 Correct 6 ms 9684 KB Output is correct
73 Correct 252 ms 33544 KB Output is correct
74 Correct 121 ms 29324 KB Output is correct
75 Correct 14 ms 10964 KB Output is correct
76 Correct 53 ms 18616 KB Output is correct
77 Correct 86 ms 21852 KB Output is correct
78 Correct 254 ms 33952 KB Output is correct
79 Correct 5 ms 9684 KB Output is correct
80 Correct 266 ms 38536 KB Output is correct
81 Correct 6 ms 10068 KB Output is correct
82 Correct 182 ms 33172 KB Output is correct
83 Correct 6 ms 9812 KB Output is correct
84 Correct 5 ms 9684 KB Output is correct
85 Correct 62 ms 20272 KB Output is correct
86 Correct 5 ms 9940 KB Output is correct
87 Correct 8 ms 10876 KB Output is correct
88 Correct 7 ms 10384 KB Output is correct
89 Correct 258 ms 33876 KB Output is correct
90 Correct 240 ms 33796 KB Output is correct
91 Correct 279 ms 37832 KB Output is correct
92 Correct 5 ms 9684 KB Output is correct