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Submission #999400

# Submission time Handle Problem Language Result Execution time Memory
999400 2024-06-15T12:31:25 Z yoav_s Star Trek (CEOI20_startrek) C++17
38 / 100
 75 ms 34128 KB 
#include <bits/stdc++.h>

using namespace std;

typedef __int128 ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll,ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()

const ll INF = 1e18;
const ll mod = 1e9 + 7;

ll modPow(ll a, ll b)
{
    if (b == 0) return 1;
    ll res = modPow(a, b / 2);
    res = (res * res) % mod;
    if (b % 2 == 1) res = (res * a) % mod;
    return res;
}

void getWinningStates(ll i, vv &graph, vb &winning, vb &visited, v &losingChildrenCount)
{
    if (visited[i]) return;
    visited[i] = true;
    for (ll x : graph[i])
    {
        if (!visited[x])
        {
            getWinningStates(x, graph, winning, visited, losingChildrenCount);
            if (!winning[x])
            {
                winning[i] = true;
                losingChildrenCount[i]++;
            }
        }
    }
}

void winningAsRoot(ll i, vv &graph, vb &visited, v &losingChildrenCount, vb &res, ll par)
{
    if (visited[i]) return;
    visited[i] = true;
    if (par != -1)
    {
        if (losingChildrenCount[i] == 0) losingChildrenCount[par]--;
        if (losingChildrenCount[par] == 0) losingChildrenCount[i]++;
    }
    res[i] = losingChildrenCount[i] > 0;
    for (ll x : graph[i])
    {
        winningAsRoot(x, graph, visited, losingChildrenCount, res, i);
    }
    if (par != -1)
    {
        if (losingChildrenCount[par] == 0) losingChildrenCount[i]--;
        if (losingChildrenCount[i] == 0) losingChildrenCount[par]++;
    }
}

ll getSubtreeSize(ll i, vv &graph, v &res)
{
    if (res[i] != 0) return 0;
    res[i] = 1;
    for (ll x : graph[i]) res[i] += getSubtreeSize(x, graph, res);
    return res[i];
}

ll solve(ll i, vv &graph, vb &isWinning, v &res, vb &visited, bool shouldWin, v &subtreeSize, ll winningCount, ll losingCount)
{
    ll N = graph.size();
    if (visited[i]) return 0;
    visited[i] = true;
    if (shouldWin)
    {
        if (isWinning[i])
        {
            ll losingChildren = 0;
            ll losingChild;
            for (ll x : graph[i])
                if (!visited[x] && !isWinning[x])
                {
                    losingChildren++;
                    losingChild = x;
                }
            if (losingChildren == 1)
            {
                res[i] += (N * (subtreeSize[i] - subtreeSize[losingChild])) % mod;
                res[i] += solve(losingChild, graph, isWinning, res, visited, false, subtreeSize, winningCount, losingCount);
                res[i] %= mod;
                return res[i];
            }
            else
            {
                res[i] = (N * subtreeSize[i]) % mod;
                return res[i];
            }
        }
        else
        {
            res[i] += losingCount;
            for (ll x : graph[i])
            {
                if (!visited[x])
                {
                    res[i] += solve(x, graph, isWinning, res, visited, false, subtreeSize, winningCount, losingCount);
                }
            }
            res[i] %= mod;
            return res[i];
        }
    }
    else
    {
        //should be losing - all children should be winning
        if (!isWinning[i])
        {
            res[i] += winningCount;
            for (ll x : graph[i])
            {
                if (!visited[x])
                    res[i] += solve(x, graph, isWinning, res, visited, true, subtreeSize, winningCount, losingCount);
            }
            res[i] %= mod;
            return res[i];
        }
        else
        {
            ll losingChildren = 0, losing;
            for (ll x : graph[i])
            {
                if (!visited[x] && !isWinning[x])
                {
                    losingChildren++; losing = x;
                }
            }
            if (losingChildren > 1) return 0;
            res[i] = solve(losing, graph, isWinning, res, visited, true, subtreeSize, winningCount, losingCount);
            return res[i];
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    long long N, D;
    cin >> N >> D;
    vv graph(N);
    for (ll i=  0; i < N - 1; i++)
    {
        long long a, b;
        cin >> a >> b;
        a--; b--;
        graph[a].pb(b);
        graph[b].pb(a);
    }
    vb isWinning(N), visited(N, false);
    v losingChildrenCount(N, 0);
    getWinningStates(0, graph, isWinning, visited, losingChildrenCount);
    vb winAsRoot(N, false);
    visited = vb(N, false);
    winningAsRoot(0, graph, visited, losingChildrenCount, winAsRoot, -1);
    ll winningCount = 0, losingCount = 0;
    for (auto x : winAsRoot)
    {
        if (x) winningCount++;
        else losingCount++;
    }
    v subtreeSize(N, 0);
    getSubtreeSize(0, graph, subtreeSize);
    v dp(N, 0);
    visited = vb(N, false);
    solve(0, graph, isWinning, dp, visited, true, subtreeSize, winningCount, losingCount);
    cout << (long long)dp[0] << "\n";
    return 0;
}

Compilation message

startrek.cpp: In function 'll solve(ll, vv&, vb&, v&, vb&, bool, v&, ll, ll)':
startrek.cpp:155:27: warning: 'losing' may be used uninitialized in this function [-Wmaybe-uninitialized]
  155 |             res[i] = solve(losing, graph, isWinning, res, visited, true, subtreeSize, winningCount, losingCount);
      |                      ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 344 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 59 ms 20820 KB Output is correct
13 Correct 75 ms 34128 KB Output is correct
14 Correct 36 ms 13264 KB Output is correct
15 Correct 44 ms 13964 KB Output is correct
16 Correct 46 ms 13908 KB Output is correct

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Incorrect 1 ms 348 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 59 ms 20820 KB Output is correct
13 Correct 75 ms 34128 KB Output is correct
14 Correct 36 ms 13264 KB Output is correct
15 Correct 44 ms 13964 KB Output is correct
16 Correct 46 ms 13908 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Incorrect 1 ms 348 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -