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Submission #944261

# Submission time Handle Problem Language Result Execution time Memory
944261 2024-03-12T13:08:30 Z LucaIlie Love Polygon (BOI18_polygon) C++17
100 / 100
 164 ms 25620 KB 
#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 1e5;
int n;
bool vis[MAX_N + 1], isOnCycle[MAX_N + 1];
int repr[MAX_N + 1], parent[MAX_N + 1], sizee[MAX_N + 1], minChanges[MAX_N + 1][2], dp1[MAX_N + 1], dp2[MAX_N + 1];
vector <int> adj[MAX_N + 1];
unordered_map <string, int> nameToId;

void findCycles( int u, int r ) {
    repr[u] = r;
    for ( int v: adj[u] ) {
        if ( repr[v] == r ) {
            isOnCycle[u] = true;
            return;
        }

        if ( repr[v] == 0 )
            findCycles( v, r );

        if ( isOnCycle[v] ) {
            isOnCycle[u] = true;
            return;
        }
    }
}

void detectCycles() {
    for ( int v = 1; v <= n; v++ )
        vis[v] = false;

    for ( int v = 1; v <= n; v++ ) {
        if ( vis[v] )
            continue;
        findCycles( v, v );
    }
}

void calc( int u ) {
    sizee[u] = 1;
    for ( int v: adj[u] ) {
        if ( isOnCycle[v] )
            continue;

        calc( v );

        minChanges[u][false] += minChanges[v][true];
        sizee[u] += sizee[v];
    }

    minChanges[u][true] = minChanges[u][false] + 1;
    for ( int v: adj[u] ) {
        if ( isOnCycle[v] )
            continue;

        minChanges[u][true] = min( minChanges[u][true], minChanges[u][false] - minChanges[v][true] + minChanges[v][false] + 1 );
    }
}

int main() {
    cin >> n;
    int id = 0;
    for ( int i = 0; i < n; i++ ) {
        string s, t;
        cin >> s >> t;
        nameToId[s] = (nameToId[s] == 0 ? ++id : nameToId[s]);
        nameToId[t] = (nameToId[t] == 0 ? ++id : nameToId[t]);
        parent[nameToId[s]] = nameToId[t];
        adj[nameToId[t]].push_back( nameToId[s] );
        //cout << nameToId[s] << " " << nameToId[t] << "\n";
    }

    if ( n % 2 == 1 ) {
        cout << -1 << "\n";
        return 0;
    }

    detectCycles();

    for ( int u = 1; u <= n; u++ ) {
        if ( !isOnCycle[u] )
            continue;
        calc( u );
    }

    for ( int v = 1; v <= n; v++ )
        vis[v] = false;
    int ans = 0;
    for ( int v = 1; v <= n; v++ ) {
        if ( !isOnCycle[v] || vis[v] )
            continue;

        vector <int> cycle;
        cycle.push_back( v );
        int u = v;
        do {
            vis[u] = true;
            u = parent[u];
            cycle.push_back( u );
        } while ( u != v );

        if ( cycle.size() == 2 ) {
            ans += minChanges[cycle[0]][true];
            continue;
        }
        if ( cycle.size() == 3 ) {
            ans += minChanges[cycle[0]][false] + minChanges[cycle[1]][false];
            continue;
        }

        dp1[1] = 0;
        dp2[1] = minChanges[cycle[1]][true];
        dp1[0] = n;
        //printf( "%d %d %d\n", cycle[1], dp1[1], dp2[1] );
        for ( int i = 2; i < cycle.size(); i++ ) {
            dp1[i] = min( dp1[i - 1] + minChanges[cycle[i]][true], dp1[i - 2] + minChanges[cycle[i - 1]][false] + minChanges[cycle[i]][false] + 1 );
            dp2[i] = min( dp2[i - 1] + minChanges[cycle[i]][true], dp2[i - 2] + minChanges[cycle[i - 1]][false] + minChanges[cycle[i]][false] + 1 );
            //printf( "%d %d %d\n", cycle[i], dp1[i], dp2[i] );
        }

        ans += min( dp2[cycle.size() - 1], dp1[cycle.size() - 2] +  minChanges[cycle.back()][false] + minChanges[cycle[1]][false] + 1 );
        //printf( "baa %d %d\n", dp2[cycle.size() - 1], dp1[cycle.size() - 2] +  minChanges[cycle.back()][false] + minChanges[cycle[1]][false] + 1 );
    }

    cout << ans << "\n";

    return 0;
}

Compilation message

polygon.cpp: In function 'int main()':
polygon.cpp:117:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |         for ( int i = 2; i < cycle.size(); i++ ) {
      |                          ~~^~~~~~~~~~~~~~

Subtask #1
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4700 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 1 ms 4720 KB Output is correct
9 Correct 2 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 1 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 1 ms 4700 KB Output is correct
14 Correct 1 ms 4700 KB Output is correct
15 Correct 1 ms 4724 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4936 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 115 ms 22636 KB Output is correct
5 Correct 103 ms 16416 KB Output is correct
6 Correct 126 ms 23488 KB Output is correct
7 Correct 113 ms 15772 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 162 ms 15556 KB Output is correct
2 Correct 128 ms 17384 KB Output is correct
3 Correct 87 ms 16252 KB Output is correct
4 Correct 105 ms 14312 KB Output is correct
5 Correct 164 ms 23552 KB Output is correct
6 Correct 101 ms 14788 KB Output is correct
7 Correct 101 ms 14788 KB Output is correct
8 Correct 114 ms 15304 KB Output is correct
9 Correct 95 ms 14276 KB Output is correct
10 Correct 82 ms 13500 KB Output is correct
11 Correct 1 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 1 ms 4952 KB Output is correct
14 Correct 1 ms 4696 KB Output is correct

Subtask #4
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4700 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 1 ms 4720 KB Output is correct
9 Correct 2 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 1 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 1 ms 4700 KB Output is correct
14 Correct 1 ms 4700 KB Output is correct
15 Correct 1 ms 4724 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct
17 Correct 1 ms 4936 KB Output is correct
18 Correct 1 ms 4700 KB Output is correct
19 Correct 115 ms 22636 KB Output is correct
20 Correct 103 ms 16416 KB Output is correct
21 Correct 126 ms 23488 KB Output is correct
22 Correct 113 ms 15772 KB Output is correct
23 Correct 162 ms 15556 KB Output is correct
24 Correct 128 ms 17384 KB Output is correct
25 Correct 87 ms 16252 KB Output is correct
26 Correct 105 ms 14312 KB Output is correct
27 Correct 164 ms 23552 KB Output is correct
28 Correct 101 ms 14788 KB Output is correct
29 Correct 101 ms 14788 KB Output is correct
30 Correct 114 ms 15304 KB Output is correct
31 Correct 95 ms 14276 KB Output is correct
32 Correct 82 ms 13500 KB Output is correct
33 Correct 1 ms 4700 KB Output is correct
34 Correct 1 ms 4700 KB Output is correct
35 Correct 1 ms 4952 KB Output is correct
36 Correct 1 ms 4696 KB Output is correct
37 Correct 106 ms 18148 KB Output is correct
38 Correct 107 ms 18416 KB Output is correct
39 Correct 104 ms 17132 KB Output is correct
40 Correct 100 ms 16840 KB Output is correct
41 Correct 133 ms 17164 KB Output is correct
42 Correct 120 ms 17352 KB Output is correct
43 Correct 102 ms 17488 KB Output is correct
44 Correct 104 ms 17352 KB Output is correct
45 Correct 116 ms 17344 KB Output is correct
46 Correct 154 ms 17344 KB Output is correct
47 Correct 92 ms 16580 KB Output is correct
48 Correct 100 ms 17752 KB Output is correct
49 Correct 144 ms 19740 KB Output is correct
50 Correct 86 ms 18372 KB Output is correct
51 Correct 138 ms 16344 KB Output is correct
52 Correct 118 ms 25620 KB Output is correct
53 Correct 98 ms 16924 KB Output is correct
54 Correct 99 ms 17092 KB Output is correct
55 Correct 120 ms 17340 KB Output is correct
56 Correct 116 ms 16376 KB Output is correct
57 Correct 88 ms 15904 KB Output is correct
58 Correct 1 ms 4696 KB Output is correct
59 Correct 1 ms 4700 KB Output is correct
60 Correct 1 ms 4700 KB Output is correct
61 Correct 1 ms 4700 KB Output is correct
62 Correct 1 ms 4700 KB Output is correct
63 Correct 1 ms 4700 KB Output is correct
64 Correct 1 ms 4700 KB Output is correct
65 Correct 104 ms 24732 KB Output is correct
66 Correct 127 ms 18620 KB Output is correct
67 Correct 118 ms 25540 KB Output is correct
68 Correct 92 ms 17892 KB Output is correct
69 Correct 1 ms 4700 KB Output is correct
70 Correct 1 ms 4700 KB Output is correct
71 Correct 1 ms 4696 KB Output is correct
72 Correct 1 ms 4700 KB Output is correct
73 Correct 1 ms 4700 KB Output is correct
74 Correct 1 ms 4700 KB Output is correct
75 Correct 1 ms 4700 KB Output is correct
76 Correct 1 ms 4700 KB Output is correct
77 Correct 1 ms 4700 KB Output is correct
78 Correct 1 ms 4700 KB Output is correct
79 Correct 1 ms 4700 KB Output is correct
80 Correct 1 ms 4700 KB Output is correct
81 Correct 1 ms 4700 KB Output is correct
82 Correct 2 ms 4724 KB Output is correct
83 Correct 2 ms 4700 KB Output is correct