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답안 #999417

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
999417 2024-06-15T12:52:39 Z yoav_s Star Trek (CEOI20_startrek) C++17
38 / 100
 47 ms 21588 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long 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];
}

p operator+(p a, p b)
{
    return p(a.f + b.f, a.s + b.s);
}

void operator+=(p &a, p b)
{
    a.f += b.f; a.s += b.s;
}

p operator%(p a, ll mod)
{
    return p(a.f % mod, a.s % mod);
}

void operator%=(p &a, ll mod)
{
    a = a % mod;
}

p solve(ll i, vv &graph, vb &isWinning, vp &res, vb &visited, bool shouldWin, v &subtreeSize)
{
    ll N = graph.size();
    assert(!visited[i]);
    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].f += (N * (subtreeSize[i] - subtreeSize[losingChild])) % mod;
                res[i] += solve(losingChild, graph, isWinning, res, visited, false, subtreeSize);
                res[i] %= mod;
                return res[i];
            }
            else
            {
                res[i] = p((N * subtreeSize[i]) % mod, 0);
                return res[i];
            }
        }
        else
        {
            res[i].s += mod - 1; res[i].f += N;
            for (ll x : graph[i])
            {
                if (!visited[x])
                {
                    res[i] += solve(x, graph, isWinning, res, visited, false, subtreeSize);
                }
            }
            res[i] %= mod;
            return res[i];
        }
    }
    else
    {
        //should be losing - all children should be winning
        if (!isWinning[i])
        {
            res[i].s++;
            for (ll x : graph[i])
            {
                if (!visited[x])
                    res[i] += solve(x, graph, isWinning, res, visited, true, subtreeSize);
            }
            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 p(0, 0);
            res[i] = solve(losing, graph, isWinning, res, visited, true, subtreeSize);
            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);
    vp dp(N, p(0, 0));
    visited = vb(N, false);
    solve(0, graph, isWinning, dp, visited, true, subtreeSize);
    cout << (dp[0].f + dp[0].s * winningCount) % mod << "\n";
    return 0;
}

Compilation message

startrek.cpp: In function 'p solve(ll, vv&, vb&, vp&, vb&, bool, v&)':
startrek.cpp:175:85: warning: 'losing' may be used uninitialized in this function [-Wmaybe-uninitialized]
  175 |             res[i] = solve(losing, graph, isWinning, res, visited, true, subtreeSize);
      |                                                                                     ^

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 348 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

# 결과 실행 시간 메모리 Grader output
1 Incorrect 0 ms 348 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 0 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 348 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

# 결과 실행 시간 메모리 Grader output
1 Correct 0 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 348 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 600 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

# 결과 실행 시간 메모리 Grader output
1 Correct 0 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 348 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 600 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 39 ms 14164 KB Output is correct
13 Correct 47 ms 21588 KB Output is correct
14 Correct 32 ms 9300 KB Output is correct
15 Correct 45 ms 9356 KB Output is correct
16 Correct 43 ms 9556 KB Output is correct

Subtask #6
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 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 348 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 600 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 0 ms 348 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 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 348 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 600 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 39 ms 14164 KB Output is correct
13 Correct 47 ms 21588 KB Output is correct
14 Correct 32 ms 9300 KB Output is correct
15 Correct 45 ms 9356 KB Output is correct
16 Correct 43 ms 9556 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Incorrect 0 ms 348 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 348 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -