답안 #932404

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
932404	2024-02-23T09:39:32 Z	LucaIlie	Star Trek (CEOI20_startrek)	C++17	38 / 100	83 ms	18056 KB

startrek

#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], reach[MAX_N + 1], critical[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 dfsCalcReach( int u, int p ) {
    if ( p == 0 )
        reach[u] = u;
    else {
        if ( canWin[u] ) {
            if ( canWin[p] )
                reach[u] = u;
            else
                reach[u] = reach[p];
        } else {
            if ( countChildrenLosers[p] >= 2 )
                reach[u] = u;
            else
                reach[u] = reach[p];
        }
    }

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

int losers = 0, c = 0;
void reroot( int u, int p ) {
    losers += !canWin[u];
    c += (canWin[u] ? 1 : -1) * critical[u];

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

        countChildrenLosers[u] -= (!canWin[v]);
        canWin[u] = (countChildrenLosers[u] > 0);
        countChildrenLosers[v] += (!canWin[u]);
        canWin[v] = (countChildrenLosers[v] > 0);

        reroot( v, u );


        countChildrenLosers[v] -= (!canWin[u]);
        canWin[v] = (countChildrenLosers[v] > 0);
        countChildrenLosers[u] += (!canWin[v]);
        canWin[u] = (countChildrenLosers[u] > 0);
    }
}

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 );
    }

    /*for ( int r = 1; r <= n; r++ ) {
        dfsGame( r, 0 );
        dfsCalcAdd( r, 0 );
        losers += !canWin[r];
        winners += canWin[r];
        reach1[r] = 0;
        for ( int v = 1; v <= n; v++ ) {
            if ( !canWin[v] && reach[v] == r )
                reach1[r]++;
        }
        rch += (canWin[r] ? 1 : -1) * reach1[r];
    }*/

    dfsGame( 1, 0 );
    dfsCalcReach( 1, 0 );
    for ( int v = 1; v <= n; v++ ) {
        if ( !canWin[v] && reach[v] == 1 )
            critical[1]++;
    }
    reroot( 1, 0 );

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

    dfsGame( 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	1 ms	4700 KB	Output is correct
2	Incorrect	2 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	Correct	1 ms	4700 KB	Output is correct
2	Correct	2 ms	4700 KB	Output is correct
3	Runtime error	53 ms	11660 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	4704 KB	Output is correct
2	Correct	1 ms	4704 KB	Output is correct
3	Correct	1 ms	4712 KB	Output is correct
4	Correct	1 ms	4696 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	4704 KB	Output is correct
2	Correct	1 ms	4704 KB	Output is correct
3	Correct	1 ms	4712 KB	Output is correct
4	Correct	1 ms	4696 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	4704 KB	Output is correct
8	Correct	1 ms	4712 KB	Output is correct
9	Correct	1 ms	4700 KB	Output is correct
10	Correct	1 ms	4704 KB	Output is correct
11	Correct	2 ms	4724 KB	Output is correct

Subtask #5
15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	1 ms	4704 KB	Output is correct
2	Correct	1 ms	4704 KB	Output is correct
3	Correct	1 ms	4712 KB	Output is correct
4	Correct	1 ms	4696 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	4704 KB	Output is correct
8	Correct	1 ms	4712 KB	Output is correct
9	Correct	1 ms	4700 KB	Output is correct
10	Correct	1 ms	4704 KB	Output is correct
11	Correct	2 ms	4724 KB	Output is correct
12	Correct	78 ms	12640 KB	Output is correct
13	Correct	83 ms	18056 KB	Output is correct
14	Correct	64 ms	10476 KB	Output is correct
15	Correct	71 ms	10592 KB	Output is correct
16	Correct	73 ms	10592 KB	Output is correct

Subtask #6
0 / 20.0

#	결과	실행 시간	메모리	Grader output
1	Correct	1 ms	4704 KB	Output is correct
2	Correct	1 ms	4704 KB	Output is correct
3	Correct	1 ms	4712 KB	Output is correct
4	Correct	1 ms	4696 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	4704 KB	Output is correct
8	Correct	1 ms	4712 KB	Output is correct
9	Correct	1 ms	4700 KB	Output is correct
10	Correct	1 ms	4704 KB	Output is correct
11	Correct	2 ms	4724 KB	Output is correct
12	Correct	1 ms	4712 KB	Output is correct
13	Incorrect	2 ms	4712 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	4704 KB	Output is correct
2	Correct	1 ms	4704 KB	Output is correct
3	Correct	1 ms	4712 KB	Output is correct
4	Correct	1 ms	4696 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	4704 KB	Output is correct
8	Correct	1 ms	4712 KB	Output is correct
9	Correct	1 ms	4700 KB	Output is correct
10	Correct	1 ms	4704 KB	Output is correct
11	Correct	2 ms	4724 KB	Output is correct
12	Correct	78 ms	12640 KB	Output is correct
13	Correct	83 ms	18056 KB	Output is correct
14	Correct	64 ms	10476 KB	Output is correct
15	Correct	71 ms	10592 KB	Output is correct
16	Correct	73 ms	10592 KB	Output is correct
17	Correct	1 ms	4712 KB	Output is correct
18	Incorrect	2 ms	4712 KB	Output isn't correct
19	Halted	0 ms	0 KB	-

Subtask #8
0 / 15.0

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

답안 #932404

Compilation message