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답안 #932337

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
932337 2024-02-23T08:24:49 Z LucaIlie Star Trek (CEOI20_startrek) C++17
23 / 100
 1000 ms 16468 KB 
#include <bits/stdc++.h>

#define int long long

using namespace std;

const int MAX_N = 1e5;
const int MAX_D = 1e5;
const int MOD = 1e9 + 7;
bool canWin[MAX_N + 1];
int countChildrenLosers[MAX_N + 1], add[MAX_N + 1], reach[MAX_N + 1], dp[MAX_D];
vector<int> adj[MAX_N + 1];

void dfsGame( int u, int p ) {
    canWin[u] = false;
    countChildrenLosers[u] = 0;
    for ( int v: adj[u] ) {
        if ( v == p )
            continue;
        dfsGame( v, u );
        canWin[u] |= (!canWin[v]);
        countChildrenLosers[u] += (!canWin[v]);
    }
}

void dfsCalcAdd( int u, int p ) {
    if ( p == 0 ) {
        add[u] = (canWin[u] ? -1 : 1);
        reach[u] = u;
    } else {
        if ( canWin[u] ) {
            if ( canWin[p] ) {
                add[u] = -1;
                reach[u] = u;
            } else {
                add[u] = add[p] - 1;
                reach[u] = reach[p];
            }
        } else {
            if ( countChildrenLosers[p] >= 2 ) {
                add[u] = 1;
                reach[u] = u;
            } else {
                add[u] = add[p] + 1;
                reach[u] = reach[p];
            }
        }
    }

    for ( int v: adj[u] ) {
        if ( v == p )
            continue;
        dfsCalcAdd( v, u );
    }
}

int lgPut( int x, int n ) {
    if ( n == 0 )
        return 1;

    int p = lgPut( x, n / 2 );
    p = (long long)p * p % MOD;
    if ( n % 2 == 1 )
        p = (long long)p * x % MOD;

    return p;
}

signed main() {
    int n, d;

    cin >> n >> d;

    for ( int i = 0; i < n - 1; i++ ) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back( v );
        adj[v].push_back( u );
        /*adj[u + n].push_back( v + n );
        adj[v + n].push_back( u + n );
        adj[u + 2 * n].push_back( v + 2 * n );
        adj[v + 2 * n].push_back( u + 2 * n );*/
    }

    /*int an = 0;
    for ( int u = 1; u <= n; u++ ) {
        for ( int v = n + 1; v <= 2 * n; v++ ) {
            adj[u].push_back( v );
            adj[v].push_back( u );
            for ( int w = n + 1; w <= 2 * n; w++ ) {
                for ( int t = 2 * n + 1; t <= 3 * n; t++ ) {
                    adj[w].push_back( t );
                    adj[t].push_back( w );
                    dfsGame( 1, 0 );
                    if ( canWin[1] ) {
                        an++;
                        printf( "W %d-%d %d-%d\n", u, v, w, t );
                    }
                    adj[w].pop_back();
                    adj[t].pop_back();
                }
            }
            adj[u].pop_back();
            adj[v].pop_back();
        }
    }
    cout << an << "\n";*/

    int losers = 0, winners = 0, reach1Losers = 0, reach1Winners = 0;
    for ( int r = 1; r <= n; r++ ) {
        dfsGame( r, 0 );
        dfsCalcAdd( r, 0 );
        losers += !canWin[r];
        winners += canWin[r];
        for ( int v = 1; v <= n; v++ ) {
            reach1Losers += (!canWin[r] && !canWin[v] && reach[v] == 1);
            reach1Winners += (canWin[r] && !canWin[v] && reach[v] == 1);
        }
    }

    dp[0] = losers;
    for ( int i = 1; i < d; i++ )
        dp[i] = (losers * lgPut( n, 2 * d ) + (reach1Winners - reach1Losers + MOD) * dp[i - 1]) % MOD;

    dfsGame( 1, 0 );
    dfsCalcAdd( 1, 0 );

    int ans = (canWin[1] ? 0 : lgPut( n, 2 * d ) );
    for ( int v = 1; v <= n; v++ ) {
        if ( canWin[1] ) {
            if ( !canWin[v] && reach[v] == 1 )
                ans = (ans + dp[d - 1]) % MOD;
        } else {
            if ( !canWin[v] && reach[v] == 1 )
                ans = (ans - dp[d - 1]) % MOD;
        }
    }

    cout << (lgPut( n, 2 * d ) - ans + MOD) % MOD << "\n";

    return 0;
}

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4952 KB Output is correct
2 Incorrect 18 ms 4696 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 2 ms 4700 KB Output is correct
3 Runtime error 135 ms 11620 KB Execution killed with signal 11
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4716 KB Output is correct
2 Correct 1 ms 4696 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

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4716 KB Output is correct
2 Correct 1 ms 4696 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 24 ms 4696 KB Output is correct
8 Correct 30 ms 4696 KB Output is correct
9 Correct 16 ms 4700 KB Output is correct
10 Correct 23 ms 4780 KB Output is correct
11 Correct 24 ms 4700 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4716 KB Output is correct
2 Correct 1 ms 4696 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 24 ms 4696 KB Output is correct
8 Correct 30 ms 4696 KB Output is correct
9 Correct 16 ms 4700 KB Output is correct
10 Correct 23 ms 4780 KB Output is correct
11 Correct 24 ms 4700 KB Output is correct
12 Execution timed out 1050 ms 16468 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4716 KB Output is correct
2 Correct 1 ms 4696 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 24 ms 4696 KB Output is correct
8 Correct 30 ms 4696 KB Output is correct
9 Correct 16 ms 4700 KB Output is correct
10 Correct 23 ms 4780 KB Output is correct
11 Correct 24 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Incorrect 18 ms 4776 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4716 KB Output is correct
2 Correct 1 ms 4696 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 24 ms 4696 KB Output is correct
8 Correct 30 ms 4696 KB Output is correct
9 Correct 16 ms 4700 KB Output is correct
10 Correct 23 ms 4780 KB Output is correct
11 Correct 24 ms 4700 KB Output is correct
12 Execution timed out 1050 ms 16468 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4952 KB Output is correct
2 Incorrect 18 ms 4696 KB Output isn't correct
3 Halted 0 ms 0 KB -