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Submission #939581

# Submission time Handle Problem Language Result Execution time Memory
939581 2024-03-06T14:31:26 Z LucaIlie The Xana coup (BOI21_xanadu) C++17
100 / 100
 98 ms 21332 KB 
#include <bits/stdc++.h>

using namespace std;

const int INF = 1e9;

struct DP {
    int dp[2][2];

    DP operator+( const DP &b ) const {
        DP a = *this;
        DP c;

        for ( int s = 0; s < 2; s++ ) {
            for ( int t = 0; t < 2; t++ )
                c.dp[s][t] = INF;
        }

        for ( int sa = 0; sa < 2; sa++ ) {
            for ( int ta = 0; ta < 2; ta++ ) {
                for ( int sb = 0; sb < 2; sb++ ) {
                    for ( int tb = 0; tb < 2; tb++ ) {
                        if ( sb ^ ta == 1 )
                            continue;
                        c.dp[sa ^ tb][ta] = min( c.dp[sa ^ tb][ta], a.dp[sa][ta] + b.dp[sb][tb] );
                    }
                }
            }
        }

        return c;
    }
};

const int MAX_N = 1e5;
bool isTurnedOn[MAX_N + 1];
DP minSwitches[MAX_N + 1];
vector <int> adj[MAX_N + 1];

void dfs( int u, int p ) {
    for ( int s = 0; s < 2; s++ ) {
        for ( int t = 0; t < 2; t++ )
            minSwitches[u].dp[s][t] = (s ^ t == isTurnedOn[u] ? t : INF);
    }
    for ( int v: adj[u] ) {
        if ( v == p )
            continue;
        dfs( v, u );
        minSwitches[u] = minSwitches[u] + minSwitches[v];
    }

    /*printf( "%d\n", u );
    printf( "%d %d\n", minSwitches[u].dp[0][0], minSwitches[u].dp[0][1] );
    printf( "%d %d\n", minSwitches[u].dp[1][0], minSwitches[u].dp[1][1] );*/
}

int main() {
    int n;

    cin >> n;
    for ( int i = 0; i < n - 1; i++ ) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back( v );
        adj[v].push_back( u );
    }
    for ( int v = 1; v <= n; v++ )
        cin >> isTurnedOn[v];

    dfs( 1, 0 );

    int ans = min( minSwitches[1].dp[0][0], minSwitches[1].dp[0][1] );
    if ( ans <= n )
        cout << ans;
    else
        cout << "impossible\n";

    return 0;
}

Compilation message

xanadu.cpp: In member function 'DP DP::operator+(const DP&) const':
xanadu.cpp:23:38: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   23 |                         if ( sb ^ ta == 1 )
      |                                   ~~~^~~~
xanadu.cpp: In function 'void dfs(int, int)':
xanadu.cpp:43:46: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   43 |             minSwitches[u].dp[s][t] = (s ^ t == isTurnedOn[u] ? t : INF);
      |                                            ~~^~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2904 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2904 KB Output is correct
6 Correct 2 ms 2652 KB Output is correct
7 Correct 1 ms 2652 KB Output is correct
8 Correct 1 ms 2652 KB Output is correct
9 Correct 1 ms 2652 KB Output is correct
10 Correct 1 ms 2652 KB Output is correct
11 Correct 1 ms 2648 KB Output is correct
12 Correct 1 ms 2652 KB Output is correct
13 Correct 1 ms 2652 KB Output is correct
14 Correct 1 ms 2652 KB Output is correct
15 Correct 2 ms 2652 KB Output is correct
16 Correct 1 ms 2652 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 72 ms 21332 KB Output is correct
2 Correct 98 ms 21028 KB Output is correct
3 Correct 73 ms 21260 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 21260 KB Output is correct
2 Correct 71 ms 20940 KB Output is correct
3 Correct 73 ms 21308 KB Output is correct
4 Correct 72 ms 8136 KB Output is correct
5 Correct 71 ms 8788 KB Output is correct
6 Correct 66 ms 8824 KB Output is correct
7 Correct 1 ms 2648 KB Output is correct
8 Correct 25 ms 4776 KB Output is correct
9 Correct 65 ms 8824 KB Output is correct
10 Correct 66 ms 8816 KB Output is correct
11 Correct 65 ms 9716 KB Output is correct
12 Correct 72 ms 9888 KB Output is correct
13 Correct 65 ms 8480 KB Output is correct
14 Correct 68 ms 8788 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2904 KB Output is correct
6 Correct 2 ms 2652 KB Output is correct
7 Correct 1 ms 2652 KB Output is correct
8 Correct 1 ms 2652 KB Output is correct
9 Correct 1 ms 2652 KB Output is correct
10 Correct 1 ms 2652 KB Output is correct
11 Correct 1 ms 2648 KB Output is correct
12 Correct 1 ms 2652 KB Output is correct
13 Correct 1 ms 2652 KB Output is correct
14 Correct 1 ms 2652 KB Output is correct
15 Correct 2 ms 2652 KB Output is correct
16 Correct 1 ms 2652 KB Output is correct
17 Correct 72 ms 21332 KB Output is correct
18 Correct 98 ms 21028 KB Output is correct
19 Correct 73 ms 21260 KB Output is correct
20 Correct 73 ms 21260 KB Output is correct
21 Correct 71 ms 20940 KB Output is correct
22 Correct 73 ms 21308 KB Output is correct
23 Correct 72 ms 8136 KB Output is correct
24 Correct 71 ms 8788 KB Output is correct
25 Correct 66 ms 8824 KB Output is correct
26 Correct 1 ms 2648 KB Output is correct
27 Correct 25 ms 4776 KB Output is correct
28 Correct 65 ms 8824 KB Output is correct
29 Correct 66 ms 8816 KB Output is correct
30 Correct 65 ms 9716 KB Output is correct
31 Correct 72 ms 9888 KB Output is correct
32 Correct 65 ms 8480 KB Output is correct
33 Correct 68 ms 8788 KB Output is correct
34 Correct 1 ms 2648 KB Output is correct
35 Correct 1 ms 2652 KB Output is correct
36 Correct 1 ms 2652 KB Output is correct
37 Correct 1 ms 2904 KB Output is correct
38 Correct 1 ms 2652 KB Output is correct
39 Correct 1 ms 2652 KB Output is correct
40 Correct 1 ms 2652 KB Output is correct
41 Correct 1 ms 2648 KB Output is correct
42 Correct 1 ms 2652 KB Output is correct
43 Correct 2 ms 2652 KB Output is correct
44 Correct 1 ms 2652 KB Output is correct
45 Correct 71 ms 21244 KB Output is correct
46 Correct 74 ms 21016 KB Output is correct
47 Correct 80 ms 21252 KB Output is correct
48 Correct 59 ms 8020 KB Output is correct
49 Correct 65 ms 8744 KB Output is correct
50 Correct 66 ms 8784 KB Output is correct
51 Correct 1 ms 2648 KB Output is correct
52 Correct 22 ms 4696 KB Output is correct
53 Correct 71 ms 8784 KB Output is correct
54 Correct 75 ms 9044 KB Output is correct
55 Correct 65 ms 9812 KB Output is correct
56 Correct 71 ms 9936 KB Output is correct
57 Correct 62 ms 8528 KB Output is correct
58 Correct 65 ms 8792 KB Output is correct
59 Correct 22 ms 4688 KB Output is correct
60 Correct 65 ms 8188 KB Output is correct
61 Correct 66 ms 8740 KB Output is correct
62 Correct 65 ms 8788 KB Output is correct
63 Correct 66 ms 8944 KB Output is correct
64 Correct 74 ms 9276 KB Output is correct
65 Correct 62 ms 9300 KB Output is correct
66 Correct 63 ms 9300 KB Output is correct
67 Correct 61 ms 9160 KB Output is correct
68 Correct 64 ms 9164 KB Output is correct
69 Correct 68 ms 9200 KB Output is correct
70 Correct 59 ms 9160 KB Output is correct