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답안 #567127

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
567127 2022-05-23T08:18:12 Z azberjibiou Star Trek (CEOI20_startrek) C++17
100 / 100
 94 ms 15868 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];
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_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;
}
ll mypow(ll a, ll b)
{
    if(b==0)    return 1;
    if(b==1)    return f(a);
    ll tmp=mypow(a, b/2);
    tmp*=tmp;   tmp%=MOD;
    if(b%2) tmp*=a; tmp%=MOD;
    return tmp;
}
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++)
    {
        par2[i]=i;
        if(degL[i]==1) leafw2[i]=1;
        if(!W[i])   sizl2[i]=1;
    }
    for(int i=1;i<=N;i++)   for(int ele : v[i]) if(degL[ele]<3 && !W[i]) onion(i, ele);
    for(int i=1;i<=N;i++)   if(W[i] && degL[i]==0 && match[i]==0)   dfs_match(i, -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=f(k2);
    for(int i=1;i<=N;i++)   if(findpar(i)==i)   k2+=sizl2[i]*(sizl2[i]-leafw2[i]), k2=f(k2);
    ll recur;
    if(D==1)    recur=numw;
    else if(k2==0)  recur=mypow(N, 2*(D-1));
    else    recur=f(f(f(f(f(N*N)*k1)+f(N*k2))*f(mypow(N, 2*(D-1))-mypow(MOD-k2, D-1)))*mypow(f(N*N+k2), MOD-2))+f(f((D%2 ? 1 : MOD-1)*numw)*mypow(k2, D-1));
    recur=f(recur);
    ll powN=mypow(N, 2*D-1);
    if(W[1])
    {
        ll ans=powN*N%MOD;
        if(degL[1]==0)  ans-=(powN-recur)*swapL1[1]; ans=f(ans);
        if(degL[1]==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);
    }
}

Compilation message

startrek.cpp: In function 'll mypow(ll, ll)':
startrek.cpp:92:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   92 |     if(b%2) tmp*=a; tmp%=MOD;
      |     ^~
startrek.cpp:92:21: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   92 |     if(b%2) tmp*=a; tmp%=MOD;
      |                     ^~~
startrek.cpp: In function 'int main()':
startrek.cpp:123:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  123 |     for(int i=1;i<=N;i++)   k2-=swapL1[i];  k2=f(k2);
      |     ^~~
startrek.cpp:123:45: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  123 |     for(int i=1;i<=N;i++)   k2-=swapL1[i];  k2=f(k2);
      |                                             ^~
startrek.cpp:134:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  134 |         if(degL[1]==0)  ans-=(powN-recur)*swapL1[1]; ans=f(ans);
      |         ^~
startrek.cpp:134:54: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  134 |         if(degL[1]==0)  ans-=(powN-recur)*swapL1[1]; ans=f(ans);
      |                                                      ^~~
startrek.cpp:135:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  135 |         if(degL[1]==1)  ans-=(powN-recur)*sizl2[findpar(1)]; ans=f(ans);
      |         ^~
startrek.cpp:135:62: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  135 |         if(degL[1]==1)  ans-=(powN-recur)*sizl2[findpar(1)]; ans=f(ans);
      |                                                              ^~~

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2772 KB Output is correct

Subtask #2
7.0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2680 KB Output is correct
5 Correct 2 ms 2696 KB Output is correct

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 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 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 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 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 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 73 ms 13284 KB Output is correct
13 Correct 81 ms 13176 KB Output is correct
14 Correct 54 ms 10512 KB Output is correct
15 Correct 72 ms 11392 KB Output is correct
16 Correct 62 ms 11332 KB Output is correct

Subtask #6
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 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 2 ms 2644 KB Output is correct
13 Correct 2 ms 2772 KB Output is correct
14 Correct 1 ms 2700 KB Output is correct
15 Correct 2 ms 2644 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 2 ms 2644 KB Output is correct
18 Correct 2 ms 2676 KB Output is correct
19 Correct 2 ms 2644 KB Output is correct
20 Correct 2 ms 2644 KB Output is correct
21 Correct 2 ms 2772 KB Output is correct
22 Correct 2 ms 2808 KB Output is correct
23 Correct 2 ms 2776 KB Output is correct
24 Correct 2 ms 2772 KB Output is correct
25 Correct 2 ms 2772 KB Output is correct
26 Correct 2 ms 2772 KB Output is correct
27 Correct 3 ms 2772 KB Output is correct
28 Correct 2 ms 2772 KB Output is correct
29 Correct 2 ms 2772 KB Output is correct
30 Correct 2 ms 2772 KB Output is correct

Subtask #7
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 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 73 ms 13284 KB Output is correct
13 Correct 81 ms 13176 KB Output is correct
14 Correct 54 ms 10512 KB Output is correct
15 Correct 72 ms 11392 KB Output is correct
16 Correct 62 ms 11332 KB Output is correct
17 Correct 2 ms 2644 KB Output is correct
18 Correct 2 ms 2772 KB Output is correct
19 Correct 1 ms 2700 KB Output is correct
20 Correct 2 ms 2644 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 2 ms 2676 KB Output is correct
24 Correct 2 ms 2644 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2772 KB Output is correct
27 Correct 2 ms 2808 KB Output is correct
28 Correct 2 ms 2776 KB Output is correct
29 Correct 2 ms 2772 KB Output is correct
30 Correct 2 ms 2772 KB Output is correct
31 Correct 2 ms 2772 KB Output is correct
32 Correct 3 ms 2772 KB Output is correct
33 Correct 2 ms 2772 KB Output is correct
34 Correct 2 ms 2772 KB Output is correct
35 Correct 2 ms 2772 KB Output is correct
36 Correct 81 ms 13608 KB Output is correct
37 Correct 86 ms 13584 KB Output is correct
38 Correct 51 ms 10964 KB Output is correct
39 Correct 70 ms 11888 KB Output is correct
40 Correct 62 ms 11748 KB Output is correct
41 Correct 78 ms 14160 KB Output is correct
42 Correct 72 ms 12672 KB Output is correct
43 Correct 45 ms 10172 KB Output is correct
44 Correct 94 ms 11744 KB Output is correct
45 Correct 62 ms 11728 KB Output is correct

Subtask #8
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2772 KB Output is correct
3 Correct 1 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2680 KB Output is correct
7 Correct 2 ms 2696 KB Output is correct
8 Correct 2 ms 2644 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2772 KB Output is correct
15 Correct 2 ms 2772 KB Output is correct
16 Correct 2 ms 2772 KB Output is correct
17 Correct 2 ms 2772 KB Output is correct
18 Correct 2 ms 2772 KB Output is correct
19 Correct 73 ms 13284 KB Output is correct
20 Correct 81 ms 13176 KB Output is correct
21 Correct 54 ms 10512 KB Output is correct
22 Correct 72 ms 11392 KB Output is correct
23 Correct 62 ms 11332 KB Output is correct
24 Correct 2 ms 2644 KB Output is correct
25 Correct 2 ms 2772 KB Output is correct
26 Correct 1 ms 2700 KB Output is correct
27 Correct 2 ms 2644 KB Output is correct
28 Correct 2 ms 2644 KB Output is correct
29 Correct 2 ms 2644 KB Output is correct
30 Correct 2 ms 2676 KB Output is correct
31 Correct 2 ms 2644 KB Output is correct
32 Correct 2 ms 2644 KB Output is correct
33 Correct 2 ms 2772 KB Output is correct
34 Correct 2 ms 2808 KB Output is correct
35 Correct 2 ms 2776 KB Output is correct
36 Correct 2 ms 2772 KB Output is correct
37 Correct 2 ms 2772 KB Output is correct
38 Correct 2 ms 2772 KB Output is correct
39 Correct 3 ms 2772 KB Output is correct
40 Correct 2 ms 2772 KB Output is correct
41 Correct 2 ms 2772 KB Output is correct
42 Correct 2 ms 2772 KB Output is correct
43 Correct 81 ms 13608 KB Output is correct
44 Correct 86 ms 13584 KB Output is correct
45 Correct 51 ms 10964 KB Output is correct
46 Correct 70 ms 11888 KB Output is correct
47 Correct 62 ms 11748 KB Output is correct
48 Correct 78 ms 14160 KB Output is correct
49 Correct 72 ms 12672 KB Output is correct
50 Correct 45 ms 10172 KB Output is correct
51 Correct 94 ms 11744 KB Output is correct
52 Correct 62 ms 11728 KB Output is correct
53 Correct 73 ms 14332 KB Output is correct
54 Correct 90 ms 15868 KB Output is correct
55 Correct 42 ms 9832 KB Output is correct
56 Correct 76 ms 14192 KB Output is correct
57 Correct 61 ms 12612 KB Output is correct
58 Correct 64 ms 12592 KB Output is correct
59 Correct 65 ms 12488 KB Output is correct
60 Correct 56 ms 12492 KB Output is correct