oj.uz

Submission #567000

# Submission time Handle Problem Language Result Execution time Memory
567000 2022-05-23T07:11:18 Z azberjibiou Star Trek (CEOI20_startrek) C++17
38 / 100
 1000 ms 16324 KB 
#include <bits/stdc++.h>
#define gibon ios::sync_with_stdio(false); cin.tie(0);
#define fir first
#define sec second
#define pdd pair<long double, long double>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ld long double
#define pmax pair<__int128, __int128>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
typedef long long ll;
using namespace std;
int dx[4]= {0, 1, 0, -1}, dy[4]= {1, 0, -1, 0};
int ddx[8]={1, 1, 0, -1, -1, -1, 0, 1}, ddy[8]={0, 1, 1, 1, 0, -1, -1, -1};
const int mxN=100025;
const int mxM=300005;
const int mxK=1000000000;
const ll MOD=1000'000'007;
const ll INF=1000000000000000005;
ll N, D;
vector <int> v[mxN];
int outw[mxN];
int downw[mxN], upw[mxN];
bool W[mxN];
ll degL[mxN];
vector <int> v2[mxN];
ll leafw2[mxN], sizl2[mxN], par2[mxN];
ll numw;
int match[mxN];
ll swapL1[mxN];
void dfs_downw(int now, int pre)
{
    for(int nxt : v[now])   if(nxt!=pre)
    {
        dfs_downw(nxt, now);
    }
    downw[now]=(outw[now]==0 ? 1 : 0);
    if(now!=1)  outw[pre]+=downw[now];
}
void dfs_upw(int now, int pre)
{
    if(now!=1)
    {
        upw[now]=(outw[pre]-downw[now]==0 ? 1 : 0);
        outw[now]+=upw[now];
    }
    for(int nxt : v[now])   if(nxt!=pre)
    {
        dfs_upw(nxt, now);
    }
}
int findpar(int a)
{
    return (par2[a]==a ? a : par2[a]=findpar(par2[a]));
}
void onion(int a, int b)
{
    int p=findpar(a), q=findpar(b);
    par2[p]=q;  sizl2[q]+=sizl2[p]; leafw2[q]+=leafw2[p];
}
int dfs_match(int now, int pre)
{
    for(int nxt : v[now])   if(nxt!=pre && W[nxt] && degL[nxt]==0)
    {
        int tmp=dfs_match(nxt, now);
        if(tmp!=0)  match[now]=tmp, match[tmp]=now;
    }
    if(match[now])  return 0;
    else    return now;
}
int dfs_1(int now)
{
    int sum=1;
    for(int nxt : v[match[now]])    if(nxt!=now && degL[nxt]==0)
    {
        sum+=dfs_1(nxt);
    }
    return sum;
}
int dfs_swap(int now)
{
    if(swapL1[now]!=0)  return swapL1[now];
    ll sum=1;
    for(int nxt : v[match[now]])    if(nxt!=now && W[nxt] && degL[nxt]==0)
    {
        sum+=dfs_swap(nxt);
    }
    return swapL1[now]=sum;
}
ll f(ll a)
{
    return (a%MOD+MOD)%MOD;
}
int main()
{
    gibon
    cin >> N >> D;
    for(int i=1;i<N;i++)
    {
        int a, b;   cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs_downw(1, -1);
    dfs_upw(1, -1);
    for(int i=1;i<=N;i++)
    {
        W[i]=(outw[i]>=1);
        numw+=W[i];
    }
    for(int i=1;i<=N;i++)
    {
        for(int ele : v[i])
        {
            if(!W[ele]) degL[i]++;
        }
    }
    for(int i=1;i<=N;i++)
    {
        if(!W[i])
        {
            for(int ele : v[i]) if(degL[ele]<3) v2[i].push_back(ele);
        }
        else if(degL[i]<3)
        {
            for(int ele : v[i]) if(!W[ele]) v2[i].push_back(ele);
        }
    }
    for(int i=1;i<=N;i++)
    {
        par2[i]=i;
        if(v2[i].size()==1 && W[i]) leafw2[i]=1;
        if(!W[i])   sizl2[i]=1;
    }
    for(int i=1;i<=N;i++)
    {
        for(int ele : v2[i])    if(ele<i)
        {
            onion(ele, i);
        }
    }
    dfs_match(1, -1);
    for(int i=1;i<=N;i++)   if(W[i] && degL[i]==0)  dfs_swap(i);
    ll k1=numw, k2=0;
    for(int i=1;i<=N;i++)   k2+=swapL1[i];
    k2%=MOD;
    for(int i=1;i<=N;i++)   if(findpar(i)==i)   k2+=sizl2[i]*(sizl2[i]-leafw2[i]), k2%=MOD;
    ll recur=numw;
    ll powN=N;
    for(int i=1;i<=D-1;i++)
    {
        recur=k1*powN%MOD*N%MOD-k2*powN%MOD+k2*recur%MOD;
        recur=(recur%MOD+MOD)%MOD;
        powN=powN*N%MOD*N%MOD;
    }
    if(W[1])
    {
        ll ans=powN*N%MOD;
        if(degL[1]==0)  ans-=(powN-recur)*dfs_1(1); ans=f(ans);
        if(v2[1].size()==1) ans-=(powN-recur)*sizl2[findpar(1)]; ans=f(ans);
        cout << ans;
    }
    else
    {
        ll ans=0;
        ans+=(powN-recur)*sizl2[findpar(1)];
        cout << f(ans);
    }
}
/*
15 1
11 10
2 1
13 3
14 2
1 3
9 10
6 7
9 4
1 6
3 12
8 11
0 14
5 13
12 9
*/

Compilation message

startrek.cpp: In function 'int main()':
startrek.cpp:161:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  161 |         if(degL[1]==0)  ans-=(powN-recur)*dfs_1(1); ans=f(ans);
      |         ^~
startrek.cpp:161:53: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  161 |         if(degL[1]==0)  ans-=(powN-recur)*dfs_1(1); ans=f(ans);
      |                                                     ^~~
startrek.cpp:162:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  162 |         if(v2[1].size()==1) ans-=(powN-recur)*sizl2[findpar(1)]; ans=f(ans);
      |         ^~
startrek.cpp:162:66: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  162 |         if(v2[1].size()==1) ans-=(powN-recur)*sizl2[findpar(1)]; ans=f(ans);
      |                                                                  ^~~

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Incorrect 4 ms 5076 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Execution timed out 1084 ms 4948 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 4 ms 5168 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5160 KB Output is correct
10 Correct 3 ms 5076 KB Output is correct
11 Correct 3 ms 5076 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 4 ms 5168 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5160 KB Output is correct
10 Correct 3 ms 5076 KB Output is correct
11 Correct 3 ms 5076 KB Output is correct
12 Correct 89 ms 15948 KB Output is correct
13 Correct 101 ms 15680 KB Output is correct
14 Correct 59 ms 16324 KB Output is correct
15 Correct 111 ms 14200 KB Output is correct
16 Correct 99 ms 15684 KB Output is correct

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 4 ms 5168 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5160 KB Output is correct
10 Correct 3 ms 5076 KB Output is correct
11 Correct 3 ms 5076 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Incorrect 4 ms 5164 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 4 ms 5168 KB Output is correct
8 Correct 4 ms 5076 KB Output is correct
9 Correct 3 ms 5160 KB Output is correct
10 Correct 3 ms 5076 KB Output is correct
11 Correct 3 ms 5076 KB Output is correct
12 Correct 89 ms 15948 KB Output is correct
13 Correct 101 ms 15680 KB Output is correct
14 Correct 59 ms 16324 KB Output is correct
15 Correct 111 ms 14200 KB Output is correct
16 Correct 99 ms 15684 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Incorrect 4 ms 5164 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Incorrect 4 ms 5076 KB Output isn't correct
3 Halted 0 ms 0 KB -