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Submission #466276

# Submission time Handle Problem Language Result Execution time Memory
466276 2021-08-18T12:48:21 Z ivan_tudor Star Trek (CEOI20_startrek) C++14
78 / 100
 747 ms 19076 KB 
#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const int MOD = 1e9 + 7;
int tp[N], tpr[N];
int crit[N], critr[N];
vector<int> gr[N];
void add(long long &x, long long y){
  y%=MOD;
  x+=y;
  if(x>=MOD)
    x-=MOD;
  if(x<0)
    x+=MOD;
}
void add(int &x, long long y){
  y%=MOD;
  x+=y;
  if(x>=MOD)
    x-=MOD;
  if(x<0)
    x+=MOD;
}
void dfs(int nod, int dad){
  tp[nod] = 0;
  int nr0 = 0, sum = 0, unq = 0;
  for(auto x:gr[nod]){
    if(x != dad){
      dfs(x, nod);
      if(tp[x] == 0)
        nr0++, unq = crit[x];
      sum += crit[x];
    }
  }
  if(nr0 == 0){
    tp[nod] = 0;
    crit[nod] = sum + 1;
  }
  else if(nr0 == 1){
    tp[nod] = 1;
    crit[nod] = unq;
  }
  else{
    tp[nod] = 1;
    crit[nod] = 0;
  }
}
void changeroot(int nod, int dad){
  int OLDTP = tp[nod], OLDCRIT = crit[nod];
  int nr0 = 0, sum = 0, unq = 0;
  for(auto x:gr[nod]){
    if(tp[x] == 0 )
      nr0++, unq = crit[x];
    sum += crit[x];
  }
  if(nr0 == 0)
    tp[nod] = 0;
  else
    tp[nod] = 1;
  if(tp[nod] == 0){
    crit[nod] = sum + 1;
  }
  else if(tp[nod] == 1){
    crit[nod] = 0;
    if(nr0 == 1)
      crit[nod] = unq;
  }
  critr[nod] = crit[nod];
  tpr[nod] = tp[nod];

  for(auto x:gr[nod]){
    if(x == dad)
      continue;
    int oldtp = tp[nod], oldcrit = crit[nod];
    if(tp[nod] == 0){
      tp[nod] = 0;
      crit[nod] = sum + 1 - crit[x];
    }
    else{
      if(tp[x] == 1){
        tp[nod] = 1;
        crit[nod] = oldcrit;
      }
      else{
        if(nr0 == 1){
          tp[nod] = 0;
          crit[nod] = sum + 1 - crit[x];
        }
        else if(nr0 == 2){
          tp[nod] = 1;
          int othunq = 0;
          for(auto vc:gr[nod]){
            if(vc == x)
              continue;
            if(tp[vc] == 0)
              othunq = crit[vc];
          }
          crit[nod] = othunq;
        }
        else if(nr0 >= 3){
          tp[nod] = 1;
          crit[nod] = 0;
        }
      }

    }

    changeroot(x, nod);

    tp[nod] = oldtp;
    crit[nod] = oldcrit;
  }

  tp[nod] = OLDTP;
  crit[nod] = OLDCRIT;
}
long long mat[2][2];
long long aux[2][2];
long long rez[2][2];

void multiply(long long A[2][2], long long B[2][2], long long rez[2][2]){
  for(int i = 0; i < 2; i++)
    for(int j = 0; j < 2; j++)
      rez[i][j] = 0;
  for(int i = 0; i <2; i++){
    for(int j = 0; j < 2; j++){
      for(int k = 0; k < 2; k++){
        add(rez[i][j], 1LL * A[i][k] * B[k][j]);
      }
    }
  }

}
void cpy(long long A[2][2], long long B[2][2]){
  for(int i = 0; i < 2; i++){
    for(int j = 0; j < 2; j++){
      B[i][j] = A[i][j];
    }
  }
}
void mknull(long long A[2][2]){
  for(int i = 0; i < 2; i++){
    for(int j = 0; j < 2; j++){
      A[i][j] = 0;
    }
  }
  A[0][0] = A[1][1] = 1;
}
void lgcput(long long pwr){
  mknull(rez);
  while(pwr){
    if(pwr & 1){
      multiply(mat, rez, aux);
      cpy(aux, rez);
    }
    multiply(mat, mat, aux);
    cpy(aux, mat);
    pwr/=2;
  }
}
int main()
{
  //freopen(".in","r",stdin);
  ios::sync_with_stdio(false);
  cin.tie(0),cout.tie(0);
  int n, d;
  cin>>n>>d;
  for(int i = 1; i < n; i++){
    int u, v;
    cin>>u>>v;
    gr[u].push_back(v);
    gr[v].push_back(u);
  }
  dfs(1, 0);
  changeroot(1, 0);
  long long nr0 = 0, sumc0= 0, nr1 = 0, sumc1= 0;
  for(int i = 1; i<=n; i++){
    if(tpr[i] == 0){
      nr0++;
      add(sumc0, critr[i]);
    }
    else{
      nr1++;
      add(sumc1, critr[i]);
    }
    cerr<<tpr[i]<<" "<<critr[i]<<"\n";
  }
  mat[0][0] = 1LL *(1LL * n * nr0 + sumc1 - sumc0 + MOD)%MOD;
  mat[0][1] = 1LL *(1LL * n * nr1 + sumc0 - sumc1 + MOD)%MOD;
  mat[1][0] = 1LL * n * nr0 % MOD;
  mat[1][1] = 1LL * n * nr1 % MOD;
  lgcput(d - 1);
  // puterea se afla in rez
  mat[0][0] = nr0;
  mat[0][1] = nr1;
  mat[1][0] = mat[1][1] = 0;

  multiply(mat, rez, aux);
  long long ans = 0;
  if(tpr[1] == 0){
    ans = 1LL * critr[1] * aux[0][0] % MOD;
  }
  else{
    ans = 1LL * critr[1] * aux[0][1] % MOD;
    add(ans, 1LL * (n - critr[1] + MOD)%MOD * ((aux[0][0] + aux[0][1])%MOD));
  }
  cout<<ans;
  return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 8 ms 2724 KB Output is correct

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Runtime error 6 ms 5196 KB Execution killed with signal 11
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 9 ms 2792 KB Output is correct
8 Correct 8 ms 2764 KB Output is correct
9 Correct 8 ms 2636 KB Output is correct
10 Correct 8 ms 2636 KB Output is correct
11 Correct 8 ms 2636 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 9 ms 2792 KB Output is correct
8 Correct 8 ms 2764 KB Output is correct
9 Correct 8 ms 2636 KB Output is correct
10 Correct 8 ms 2636 KB Output is correct
11 Correct 8 ms 2636 KB Output is correct
12 Correct 684 ms 13032 KB Output is correct
13 Correct 715 ms 19076 KB Output is correct
14 Correct 667 ms 8324 KB Output is correct
15 Correct 663 ms 7824 KB Output is correct
16 Correct 706 ms 7904 KB Output is correct

Subtask #6
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 9 ms 2792 KB Output is correct
8 Correct 8 ms 2764 KB Output is correct
9 Correct 8 ms 2636 KB Output is correct
10 Correct 8 ms 2636 KB Output is correct
11 Correct 8 ms 2636 KB Output is correct
12 Correct 2 ms 2636 KB Output is correct
13 Correct 8 ms 2728 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2636 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct
17 Correct 3 ms 2636 KB Output is correct
18 Correct 3 ms 2636 KB Output is correct
19 Correct 3 ms 2636 KB Output is correct
20 Correct 3 ms 2636 KB Output is correct
21 Correct 9 ms 2764 KB Output is correct
22 Correct 11 ms 2836 KB Output is correct
23 Correct 9 ms 2636 KB Output is correct
24 Correct 8 ms 2636 KB Output is correct
25 Correct 9 ms 2636 KB Output is correct
26 Correct 9 ms 2764 KB Output is correct
27 Correct 8 ms 2764 KB Output is correct
28 Correct 7 ms 2636 KB Output is correct
29 Correct 8 ms 2728 KB Output is correct
30 Correct 8 ms 2636 KB Output is correct

Subtask #7
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 9 ms 2792 KB Output is correct
8 Correct 8 ms 2764 KB Output is correct
9 Correct 8 ms 2636 KB Output is correct
10 Correct 8 ms 2636 KB Output is correct
11 Correct 8 ms 2636 KB Output is correct
12 Correct 684 ms 13032 KB Output is correct
13 Correct 715 ms 19076 KB Output is correct
14 Correct 667 ms 8324 KB Output is correct
15 Correct 663 ms 7824 KB Output is correct
16 Correct 706 ms 7904 KB Output is correct
17 Correct 2 ms 2636 KB Output is correct
18 Correct 8 ms 2728 KB Output is correct
19 Correct 2 ms 2636 KB Output is correct
20 Correct 2 ms 2636 KB Output is correct
21 Correct 2 ms 2636 KB Output is correct
22 Correct 3 ms 2636 KB Output is correct
23 Correct 3 ms 2636 KB Output is correct
24 Correct 3 ms 2636 KB Output is correct
25 Correct 3 ms 2636 KB Output is correct
26 Correct 9 ms 2764 KB Output is correct
27 Correct 11 ms 2836 KB Output is correct
28 Correct 9 ms 2636 KB Output is correct
29 Correct 8 ms 2636 KB Output is correct
30 Correct 9 ms 2636 KB Output is correct
31 Correct 9 ms 2764 KB Output is correct
32 Correct 8 ms 2764 KB Output is correct
33 Correct 7 ms 2636 KB Output is correct
34 Correct 8 ms 2728 KB Output is correct
35 Correct 8 ms 2636 KB Output is correct
36 Correct 716 ms 13160 KB Output is correct
37 Correct 747 ms 19036 KB Output is correct
38 Correct 652 ms 8128 KB Output is correct
39 Correct 705 ms 7724 KB Output is correct
40 Correct 694 ms 7940 KB Output is correct
41 Correct 732 ms 16260 KB Output is correct
42 Correct 621 ms 17612 KB Output is correct
43 Correct 607 ms 7532 KB Output is correct
44 Correct 671 ms 7956 KB Output is correct
45 Correct 702 ms 8004 KB Output is correct

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 8 ms 2724 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Runtime error 6 ms 5196 KB Execution killed with signal 11
6 Halted 0 ms 0 KB -