Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<long long> vll;
typedef vector<pair<int,int> > vpi;
typedef vector<pair<long long, long long> > vpl;
typedef pair<int,int> pii;
typedef pair<long long, long long> pll;
#define INF (int)(1e9)
#define MAXX 1.1529215e+18
#define inf 999999
#define EPS (1e-7)
#define rep(i,n) for(int i=0; i<(int)(n);i++)
#define REP(i,n) for(int i=1;i<=(int)(n);i++)
#define FOR(i,k,n) for(int i=(k);i<(int)(n);i++)
#define ALL(a)  a.begin(),a.end()
#define RALL(a) a.begin(),a.end(),greater<int>()
#define ROT(a) a.begin(),a.begin()+1,a.end()
#define RROT(a) a.begin(),a.end()-1,a.end()
#define PB push_back
#define MP make_pair
#define PI acos(-1.0)
#define sz(a) a.size()
const ll MOD = 1e9+7;
const int MAX = 10000000;
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a, T b) { if (b == 0) return a; return gcd(b, a % b); }
//cout << 'H' << endl;
/*--------------------------------------------*/

vector<vector<int>> G;
int N,K;
ll ans;
vector<int> seen;
vector<int> color;

    //cout << fixed << setprecision(10)
    cin.tie(0);
    ios::sync_with_stdio(false);
		
	cin >> N >> K;

	G.resize(N);
	seen.assign(N,0);
	color.assign(N,K-1);

	rep(i,N-1){
		int a,b;
		cin >> a >> b;
		--a;--b;
		G[a].PB(b);
		G[b].PB(a);
	}

	ans = 1;

	int st = 0;
	queue<pii> q;
	q.push(pii(0,K));

	while(!q.empty()){
		pii t = q.front();
		q.pop();
		seen[t.first] = 1;

		ans *= t.second;
		ans %= MOD;
	
		int col = K - (t.first == 0?1:2);

		for(int v:G[t.first]){
			if(!seen[v]){
				q.push(pii(v,col--));
			}
		}
	}

	cout << ans << endl;
	
}


Compiler output:
a.cc:39:5: error: 'cin' does not name a type
   39 |     cin.tie(0);
      |     ^~~
a.cc:40:5: error: specializing member 'std::basic_ios<char>::sync_with_stdio' requires 'template<>' syntax
   40 |     ios::sync_with_stdio(false);
      |     ^~~
a.cc:42:9: error: 'cin' does not name a type
   42 |         cin >> N >> K;
      |         ^~~
a.cc:44:9: error: 'G' does not name a type
   44 |         G.resize(N);
      |         ^
a.cc:45:9: error: 'seen' does not name a type
   45 |         seen.assign(N,0);
      |         ^~~~
a.cc:46:9: error: 'color' does not name a type
   46 |         color.assign(N,K-1);
      |         ^~~~~
a.cc:13:18: error: expected unqualified-id before 'for'
   13 | #define rep(i,n) for(int i=0; i<(int)(n);i++)
      |                  ^~~
a.cc:48:9: note: in expansion of macro 'rep'
   48 |         rep(i,N-1){
      |         ^~~
a.cc:48:13: error: 'i' does not name a type
   48 |         rep(i,N-1){
      |             ^
a.cc:13:31: note: in definition of macro 'rep'
   13 | #define rep(i,n) for(int i=0; i<(int)(n);i++)
      |                               ^
a.cc:48:13: error: 'i' does not name a type
   48 |         rep(i,N-1){
      |             ^
a.cc:13:42: note: in definition of macro 'rep'
   13 | #define rep(i,n) for(int i=0; i<(int)(n);i++)
      |                                          ^
a.cc:56:9: error: 'ans' does not name a type
   56 |         ans = 1;
      |         ^~~
a.cc:60:9: error: 'q' does not name a type
   60 |         q.push(pii(0,K));
      |         ^
a.cc:62:9: error: expected unqualified-id before 'while'
   62 |         while(!q.empty()){
      |         ^~~~~
a.cc:79:9: error: 'cout' does not name a type
   79 |         cout << ans << endl;
      |         ^~~~
a.cc:81:1: error: expected declaration before '}' token
   81 | }
      | ^