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답안 #630026

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
630026 2022-08-15T14:33:16 Z Vladth11 Star Trek (CEOI20_startrek) C++14
38 / 100
 93 ms 22128 KB 
#include <bits/stdc++.h>
#define C 1
#define P 0
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "

using namespace std;
typedef long long ll;
typedef pair <ll, ll> pii;
typedef pair <long double, pii> muchie;

const ll NMAX = 100001;
const ll VMAX = 101;
const ll INF = (1LL << 60);
const ll MOD = 1000000007;
const ll BLOCK = 447;
const ll base = 117;
const ll nr_of_bits = 18;
const ll inv2 = 500000004;

vector <ll> v[NMAX];
ll col[NMAX];
ll children[NMAX][2];
ll maximal[NMAX];
ll rosii[NMAX];
ll criticals[NMAX];
ll adv[NMAX];
ll sumR[NMAX][2];

void DFS(ll node, ll p){
    col[node] = P;
    for(auto x : v[node]){
        if(x == p) continue;
        DFS(x, node);
        children[node][col[x]]++;
    }
    if(children[node][C] == (ll)v[node].size() - (p != 0)){
        col[node] = P;
    }else{
        col[node] = C;
    }
    if(col[node] == P)
        rosii[node] = 1;
    for(auto x : v[node]){
        if(x == p) continue;
        if(col[node] != col[x] && children[node][C] >= (ll)v[node].size() - (p != 0) - 1){
            rosii[node] += rosii[x];
        }
        sumR[node][col[x]] += rosii[x];
    }
}

ll perdanti = 0;

void bagaR(int node, int p){
    rosii[node] = (col[node] == P);
    if(children[node][C] >= (ll)v[node].size() - (p != 0) - 1) { /// mereu facem bagaR pentru root
        rosii[node] += sumR[node][P + C - col[node]];
    }
}

void Rerooting(ll node, ll p){
    adv[node] = col[node];
    criticals[node] = rosii[node];
    if(adv[node] == P)
        perdanti++;
    for(auto x : v[node]){
        if(x == p) continue;
        ll cx = col[x], cnode = col[node];
        children[node][col[x]]--;
        sumR[node][col[x]] -= rosii[x];
        if(children[node][C] == v[node].size() - 1){
            col[node] = P;
        }else{
            col[node] = C;
        }
        bagaR(node, x);
        children[x][col[node]]++;
        sumR[x][col[node]] += rosii[node];
        if(children[x][C] == v[x].size()){
            col[x] = P;
        }else{
            col[x] = C;
        }
        bagaR(x, 0);
        Rerooting(x, node);
        children[x][col[node]]--;
        sumR[x][col[node]] -= rosii[node];
        col[x] = cx;
        bagaR(x, node);
        col[node] = cnode;
        children[node][col[x]]++;
        sumR[node][col[x]] += rosii[x];
        bagaR(node, 0);
    }
}

ll lgput(ll n, ll p){
    ll r = 1;
    while(p){
        if(p % 2){
            r *= n;
            r %= MOD;
        }
        n *= n;
        n %= MOD;
        p /= 2;
    }
    return r;
}

void add(ll &x, ll val){
    x += val;
    if(x >= MOD)
        x -= MOD;
    if(x < 0)
        x += MOD;
}

ll L[NMAX];

int main() {
    //ifstream cin(".in");
    //ofstream cout(".out");
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll n, d, i, criticalDif;
    cin >> n >> d;
    for(i = 1; i < n; i++){
        ll a, b;
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    DFS(2, 0);
    Rerooting(2, 0);
    for(i = 1; i <= n; i++){
        if(adv[i] == P){
            add(criticalDif, -criticals[i]);
        }else{
            add(criticalDif, criticals[i]);
        }
    }
    ll B = criticalDif;
    ll A = (perdanti * n) % MOD * n % MOD;
    /// L0 = perdanti
    /// L1 = A + L0 * B
    /// Li = A + Li-1 * B
    L[0] = perdanti;
    for(i = 1; i <= d - 1; i++){
        L[i] = (A + (L[i - 1] * B) % MOD) % MOD;
    }
    ll schimba = (L[d - 1] * criticals[1]) % MOD;
    if(adv[1] == P){
        cout << schimba;
    }else{
        cout << (1LL * n * n - schimba + MOD) % MOD;
    }
    return 0;
}

Compilation message

startrek.cpp: In function 'void Rerooting(ll, ll)':
startrek.cpp:72:30: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |         if(children[node][C] == v[node].size() - 1){
      |            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
startrek.cpp:80:27: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |         if(children[x][C] == v[x].size()){
      |            ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
startrek.cpp: In function 'int main()':
startrek.cpp:152:31: warning: 'criticalDif' may be used uninitialized in this function [-Wmaybe-uninitialized]
  152 |         L[i] = (A + (L[i - 1] * B) % MOD) % MOD;
      |                     ~~~~~~~~~~^~~~

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Incorrect 2 ms 2772 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 2644 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 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct

Subtask #5
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct
12 Correct 84 ms 22128 KB Output is correct
13 Correct 93 ms 20908 KB Output is correct
14 Correct 65 ms 12368 KB Output is correct
15 Correct 71 ms 12424 KB Output is correct
16 Correct 75 ms 12524 KB Output is correct

Subtask #6
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Incorrect 2 ms 2772 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 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2772 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 2 ms 2772 KB Output is correct
12 Correct 84 ms 22128 KB Output is correct
13 Correct 93 ms 20908 KB Output is correct
14 Correct 65 ms 12368 KB Output is correct
15 Correct 71 ms 12424 KB Output is correct
16 Correct 75 ms 12524 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Incorrect 2 ms 2772 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 2644 KB Output is correct
2 Incorrect 2 ms 2772 KB Output isn't correct
3 Halted 0 ms 0 KB -