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Submission #856206

# Submission time Handle Problem Language Result Execution time Memory
856206 2023-10-02T19:31:50 Z sofijavelkovska Star Trek (CEOI20_startrek) C++14
7 / 100
 2 ms 3164 KB 
#include <bits/stdc++.h>
using namespace std;

const int MAXN=1e5, MOD=1e9+7;

vector<int> adj[MAXN+1];
bool win0[MAXN+1], win1[MAXN+1];
int losechildren[MAXN+1];

long long power4(long long n)
{
    long long result=1, current=4;
    for (long long i=0; i<64; i++)
    {
        if (n&((long long)1<<i))
            result=result*current%MOD;
        current=current*current%MOD;
    }

    return result;
}

bool dfs0(int x, int t)
{
    bool possible=false;
    for (auto y : adj[x])
    {
        if (y==t)
            continue;
        if (!dfs0(y, x))
            possible=true;
    }

    return win0[x]=possible;
}

void dfs1(int x, int t)
{
    if (t==-1)
    {
        for (auto y : adj[x])
            dfs1(y, x);
        win1[x]=win0[x];

        return;
    }
    if (!win1[x])
        losechildren[t]=losechildren[t]-1;
    if (losechildren[t]==0)
        win1[t]=false;
    if (!win1[t])
        losechildren[x]=losechildren[x]+1;
    if (losechildren[x]>0)
        win1[x]=true;

    return;
}

int dfscritical(int x, int t)
{
    int critical=0;
    if (!win0[x])
    {
        critical=critical+1;
        for (auto y : adj[x])
        {
            if (y==t)
                continue;
            critical=critical+dfscritical(y, x);
        }
    }
    else
    {
        int losenodes=0;
        for (auto y : adj[x])
        {
            if (y==t)
                continue;
            if (!win0[y])
            {
                critical=critical+dfscritical(y, x);
                losenodes=losenodes+1;
            }
        }
        if (losenodes>1)
            critical=0;
    }

    return critical;
}

void countlosechildren(int x, int t)
{
    losechildren[x]=0;
    for (auto y : adj[x])
    {
        if (y==t)
            continue;
        countlosechildren(y, x);
        if (!win0[y])
            losechildren[x]=losechildren[x]+1;
    }

    return;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n, x, y, i;
    long long d, total;
    cin >> n >> d;
    for (i=0; i<n-1; i++)
    {
        cin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    if (n==2)
    {
        cout << power4(d);
        return 0;
    }
    dfs0(1, -1);
    countlosechildren(1, -1);
    dfs1(1, -1);
    //for (i=1; i<=n; i++)
      //  win1[i]=dfs1(i, -1);
    int win=0;
    for (i=1; i<=n; i++)
        if (win1[i])
            win=win+1;
    int lose=n-win;
    int critical=dfscritical(1, -1);
    /*for (i=1; i<=n; i++)
        cout << win0[i] << " ";
    cout << '\n';
    for (i=1; i<=n; i++)
        cout << win1[i] << " ";
    cout << '\n';*/
    //cout << win << " " << lose << " " << critical << '\n';
    if (win0[1])
        total=n*win+(n-critical)*lose;
    else
        total=critical*lose;

    cout << total;

    return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 2 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3164 KB Output is correct
2 Correct 1 ms 3164 KB Output is correct
3 Correct 1 ms 3164 KB Output is correct
4 Correct 1 ms 3164 KB Output is correct
5 Correct 1 ms 3164 KB Output is correct

Subtask #3
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 1 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 1 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 1 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 1 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 1 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3160 KB Output is correct
2 Incorrect 2 ms 3164 KB Output isn't correct
3 Halted 0 ms 0 KB -