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Submission #466264

# Submission time Handle Problem Language Result Execution time Memory
466264 2021-08-18T12:27:04 Z ivan_tudor Star Trek (CEOI20_startrek) C++14
78 / 100
 727 ms 20224 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 dp[N][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";
  }
  dp[0][0] = nr0;
  dp[0][1] = nr1;
  for(int i = 1; i <d; i++){
    dp[i][0] = 0;
    //vine din 0
    add(dp[i][0], 1LL * sumc0 * dp[i-1][1]);
    add(dp[i][0], 1LL * (1LL*n*nr0%MOD - sumc0 + MOD)%MOD * ((dp[i-1][0] + dp[i-1][1])%MOD));

    //vine din 1
    add(dp[i][0], 1LL * sumc1 * dp[i-1][0]);

    dp[i][1] = 0;
    //vine din 0
    add(dp[i][1], 1LL * sumc0 * dp[i-1][0]);

    //vine din 1
    add(dp[i][1], 1LL * sumc1 * dp[i - 1][1]);
    add(dp[i][1], 1LL * (1LL*n*nr1%MOD - sumc1 + MOD)%MOD * ((dp[i-1][0] + dp[i-1][1])%MOD));
  }
  long long ans = 0;
  if(tpr[1] == 0){
    ans = 1LL * critr[1] * dp[d-1][0] % MOD;
  }
  else{
    ans = 1LL * critr[1] * dp[d - 1][1] % MOD;
    add(ans, 1LL * (n - critr[1] + MOD)%MOD * ((dp[d-1][0] + dp[d-1][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 2740 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 3 ms 2764 KB Output is correct
3 Runtime error 5 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 2 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 2 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 2796 KB Output is correct
8 Correct 8 ms 2772 KB Output is correct
9 Correct 9 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 2 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 2796 KB Output is correct
8 Correct 8 ms 2772 KB Output is correct
9 Correct 9 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 727 ms 13132 KB Output is correct
13 Correct 696 ms 18984 KB Output is correct
14 Correct 672 ms 8112 KB Output is correct
15 Correct 676 ms 7932 KB Output is correct
16 Correct 673 ms 8012 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 2 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 2796 KB Output is correct
8 Correct 8 ms 2772 KB Output is correct
9 Correct 9 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 2636 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2796 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct
17 Correct 3 ms 2636 KB Output is correct
18 Correct 2 ms 2672 KB Output is correct
19 Correct 3 ms 2636 KB Output is correct
20 Correct 3 ms 2636 KB Output is correct
21 Correct 8 ms 2808 KB Output is correct
22 Correct 8 ms 2856 KB Output is correct
23 Correct 8 ms 2636 KB Output is correct
24 Correct 8 ms 2636 KB Output is correct
25 Correct 8 ms 2636 KB Output is correct
26 Correct 13 ms 4016 KB Output is correct
27 Correct 12 ms 4184 KB Output is correct
28 Correct 12 ms 4212 KB Output is correct
29 Correct 13 ms 4044 KB Output is correct
30 Correct 14 ms 3532 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 2 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 2796 KB Output is correct
8 Correct 8 ms 2772 KB Output is correct
9 Correct 9 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 727 ms 13132 KB Output is correct
13 Correct 696 ms 18984 KB Output is correct
14 Correct 672 ms 8112 KB Output is correct
15 Correct 676 ms 7932 KB Output is correct
16 Correct 673 ms 8012 KB Output is correct
17 Correct 2 ms 2636 KB Output is correct
18 Correct 8 ms 2636 KB Output is correct
19 Correct 2 ms 2636 KB Output is correct
20 Correct 2 ms 2796 KB Output is correct
21 Correct 2 ms 2636 KB Output is correct
22 Correct 3 ms 2636 KB Output is correct
23 Correct 2 ms 2672 KB Output is correct
24 Correct 3 ms 2636 KB Output is correct
25 Correct 3 ms 2636 KB Output is correct
26 Correct 8 ms 2808 KB Output is correct
27 Correct 8 ms 2856 KB Output is correct
28 Correct 8 ms 2636 KB Output is correct
29 Correct 8 ms 2636 KB Output is correct
30 Correct 8 ms 2636 KB Output is correct
31 Correct 13 ms 4016 KB Output is correct
32 Correct 12 ms 4184 KB Output is correct
33 Correct 12 ms 4212 KB Output is correct
34 Correct 13 ms 4044 KB Output is correct
35 Correct 14 ms 3532 KB Output is correct
36 Correct 695 ms 14152 KB Output is correct
37 Correct 714 ms 20224 KB Output is correct
38 Correct 691 ms 9208 KB Output is correct
39 Correct 676 ms 8908 KB Output is correct
40 Correct 723 ms 8988 KB Output is correct
41 Correct 726 ms 18684 KB Output is correct
42 Correct 660 ms 19888 KB Output is correct
43 Correct 588 ms 9688 KB Output is correct
44 Correct 701 ms 9288 KB Output is correct
45 Correct 711 ms 10564 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 2740 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 3 ms 2764 KB Output is correct
5 Runtime error 5 ms 5196 KB Execution killed with signal 11
6 Halted 0 ms 0 KB -