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답안 #931776

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
931776 2024-02-22T10:46:18 Z LucaIlie Star Trek (CEOI20_startrek) C++17
23 / 100
 1000 ms 17744 KB 
#include <bits/stdc++.h>

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][3];
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 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 );
    }

    /*int ans = 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 );
            dfsGame( 1, 0 );
            if ( canWin[1] ) {
                ans++;
                printf( "%d %d\n", u, v - n );
            }
            adj[u].pop_back();
            adj[v].pop_back();
        }
    }
    cout << ans;*/

    int pom = 0;
    int winners = 0;
    for ( int v = 1; v <= n; v++ ) {
        dfsGame( v, 0 );
        winners += canWin[v];
        int w = 0;
        for  ( int u = 1; u <= n; u++ )
            w += canWin[u];
        if (pom == 0)
            pom = w;
        if ( pom != w )
            exit( 1 );
        dp[0][!canWin[v]] = 0;
        dp[0][canWin[v]] = 1;
    }

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

    /*for ( int i = 1; i < d; i++ ) {
        //0 1 2
        for ( int prv = 0; prv < 2; prv++ ) {
            for ( int crt = 0; crt < 2; crt++ ) {
                dp[i][crt] = dp[i - 1][prv] +
            }
        }
    }*/

    int ans = 0;
    for ( int v = 1; v <= n; v++ ) {
        if ( canWin[1] ) {
            if ( canWin[v] )
                ans = (ans + n) % MOD;
            else {
                ans = (ans + winners) % MOD;
                if ( reach[v] != 1 )
                    ans = (ans + n - winners) % MOD;
            }
        } else {
            if ( !canWin[v] ) {
                if ( reach[v] == 1 )
                    ans = (ans + n - winners) % MOD;
            }
        }
    }

    cout << ans << "\n";

    return 0;
}

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4696 KB Output is correct
2 Incorrect 9 ms 4700 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1 ms 4700 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 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

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 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 13 ms 4700 KB Output is correct
8 Correct 15 ms 4700 KB Output is correct
9 Correct 8 ms 4700 KB Output is correct
10 Correct 10 ms 4700 KB Output is correct
11 Correct 11 ms 4700 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 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 13 ms 4700 KB Output is correct
8 Correct 15 ms 4700 KB Output is correct
9 Correct 8 ms 4700 KB Output is correct
10 Correct 10 ms 4700 KB Output is correct
11 Correct 11 ms 4700 KB Output is correct
12 Execution timed out 1033 ms 17744 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 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 13 ms 4700 KB Output is correct
8 Correct 15 ms 4700 KB Output is correct
9 Correct 8 ms 4700 KB Output is correct
10 Correct 10 ms 4700 KB Output is correct
11 Correct 11 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Incorrect 10 ms 4800 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 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 13 ms 4700 KB Output is correct
8 Correct 15 ms 4700 KB Output is correct
9 Correct 8 ms 4700 KB Output is correct
10 Correct 10 ms 4700 KB Output is correct
11 Correct 11 ms 4700 KB Output is correct
12 Execution timed out 1033 ms 17744 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 4696 KB Output is correct
2 Incorrect 9 ms 4700 KB Output isn't correct
3 Halted 0 ms 0 KB -