#pragma region preprocessor #ifdef LOCAL //* #define _GLIBCXX_DEBUG // gcc /*/ #define _LIBCPP_DEBUG 0 // clang //*/ #define __clock__ // #define __buffer_check__ #else #pragma GCC optimize("Ofast") // #define __buffer_check__ // #define NDEBUG #endif #define __precision__ 15 #define iostream_untie true #include #include #define __all(v) std::begin(v), std::end(v) #define __rall(v) std::rbegin(v), std::rend(v) #define __popcount(n) __builtin_popcountll(n) #define __clz32(n) __builtin_clz(n) #define __clz64(n) __builtin_clzll(n) #define __ctz32(n) __builtin_ctz(n) #define __ctz64(n) __builtin_ctzll(n) #ifdef __clock__ #include "clock.hpp" #else #define build_clock() ((void)0) #define set_clock() ((void)0) #define get_clock() ((void)0) #endif #ifdef LOCAL #include "dump.hpp" #define mesg(str) std::cerr << "[ " << __LINE__ << " : " << __FUNCTION__ << " ] " << str << "\n" #else #define dump(...) ((void)0) #define mesg(str) ((void)0) #endif #pragma endregion // preprocessor #pragma region std-overload namespace std { // hash template size_t hash_combine(size_t seed, T const &key) { return seed ^ (hash()(key) + 0x9e3779b9 + (seed << 6) + (seed >> 2)); } template struct hash> { size_t operator()(pair const &pr) const { return hash_combine(hash_combine(0, pr.first), pr.second); } }; template ::value - 1> struct tuple_hash_calc { static size_t apply(size_t seed, tuple_t const &t) { return hash_combine(tuple_hash_calc::apply(seed, t), get(t)); } }; template struct tuple_hash_calc { static size_t apply(size_t seed, tuple_t const &t) { return hash_combine(seed, get<0>(t)); } }; template struct hash> { size_t operator()(tuple const &t) const { return tuple_hash_calc>::apply(0, t); } }; // iostream template istream &operator>>(istream &is, pair &p) { return is >> p.first >> p.second; } template ostream &operator<<(ostream &os, const pair &p) { return os << p.first << ' ' << p.second; } template struct tupleis { static istream &apply(istream &is, tuple_t &t) { tupleis::apply(is, t); return is >> get(t); } }; template struct tupleis { static istream &apply(istream &is, tuple_t &t) { return is; } }; template istream &operator>>(istream &is, tuple &t) { return tupleis, tuple_size>::value - 1>::apply(is, t); } template <> istream &operator>>(istream &is, tuple<> &t) { return is; } template struct tupleos { static ostream &apply(ostream &os, const tuple_t &t) { tupleos::apply(os, t); return os << ' ' << get(t); } }; template struct tupleos { static ostream &apply(ostream &os, const tuple_t &t) { return os << get<0>(t); } }; template ostream &operator<<(ostream &os, const tuple &t) { return tupleos, tuple_size>::value - 1>::apply(os, t); } template <> ostream &operator<<(ostream &os, const tuple<> &t) { return os; } template , string>::value, nullptr_t> = nullptr> istream& operator>>(istream& is, Container &cont) { for(auto&& e : cont) is >> e; return is; } template , string>::value, nullptr_t> = nullptr> ostream& operator<<(ostream& os, const Container &cont) { bool flag = 1; for(auto&& e : cont) flag ? flag = 0 : (os << ' ', 0), os << e; return os; } } // namespace std #pragma endregion // std-overload #pragma region executive-setting namespace setting { using namespace std; using namespace chrono; system_clock::time_point start_time, end_time; long long get_elapsed_time() { end_time = system_clock::now(); return duration_cast(end_time - start_time).count(); } void print_elapsed_time() { cerr << "\n----- Exec time : " << get_elapsed_time() << " ms -----\n\n"; } void buffer_check() { char bufc; if(cin >> bufc) cerr << "\n\033[1;35mwarning\033[0m: buffer not empty.\n"; } struct setupper { setupper() { if(iostream_untie) ios::sync_with_stdio(false), cin.tie(nullptr); cout << fixed << setprecision(__precision__); #ifdef stderr_path freopen(stderr_path, "a", stderr); #endif #ifdef LOCAL cerr << fixed << setprecision(__precision__) << boolalpha << "\n----- stderr at LOCAL -----\n\n"; #endif #ifdef __clock__ start_time = system_clock::now(); atexit(print_elapsed_time); #endif #ifdef __buffer_check__ atexit(buffer_check); #endif } } __setupper; // struct setupper } // namespace setting #pragma endregion // executive-setting #pragma region fucntion-utility // lambda wrapper for recursive method. template class make_recursive { lambda_type func; public: make_recursive(lambda_type &&f) : func(std::move(f)) {} template auto operator()(Args &&... args) const { return func(*this, std::forward(args)...); } }; template T read(types... args) noexcept { typename std::remove_const::type obj(args...); std::cin >> obj; return obj; } // #define input(type, var, ...) type var{read(__VA_ARGS__)} // substitute y for x if x > y. template inline bool chmin(T &x, const T &y) { return x > y ? x = y, true : false; } // substitute y for x if x < y. template inline bool chmax(T &x, const T &y) { return x < y ? x = y, true : false; } // binary search on discrete range. template iter_type binary(iter_type __ok, iter_type __ng, pred_type pred) { assert(__ok != __ng); std::ptrdiff_t dist(__ng - __ok); while(std::abs(dist) > 1) { iter_type mid(__ok + dist / 2); if(pred(mid)) __ok = mid, dist -= dist / 2; else __ng = mid, dist /= 2; } return __ok; } // binary search on real numbers. template long double binary(long double __ok, long double __ng, const long double eps, pred_type pred) { assert(__ok != __ng); while(std::abs(__ok - __ng) > eps) { long double mid{(__ok + __ng) / 2}; (pred(mid) ? __ok : __ng) = mid; } return __ok; } // trinary search on discrete range. template iter_type trinary(iter_type __first, iter_type __last, comp_type comp) { assert(__first < __last); std::ptrdiff_t dist(__last - __first); while(dist > 2) { iter_type __left(__first + dist / 3), __right = (__first + dist * 2 / 3); if(comp(__left, __right)) __last = __right, dist = dist * 2 / 3; else __first = __left, dist -= dist / 3; } if(dist > 1 && comp(next(__first), __first)) ++__first; return __first; } // trinary search on real numbers. template long double trinary(long double __first, long double __last, const long double eps, comp_type comp) { assert(__first < __last); while(__last - __first > eps) { long double __left{(__first * 2 + __last) / 3}, __right{(__first + __last * 2) / 3}; if(comp(__left, __right)) __last = __right; else __first = __left; } return __first; } // size of array. template size_t size(A (&array)[N]) { return N; } // be careful that val is type-sensitive. template void init(A (&array)[N], const T &val) { std::fill((T*)array, (T*)(array + N), val); } #pragma endregion // function-utility #pragma region using-alias using namespace std; using i32 = int_least32_t; using i64 = int_least64_t; using u32 = uint_least32_t; using u64 = uint_least64_t; using p32 = pair; using p64 = pair; template > using heap = priority_queue, Comp>; template using hashset = unordered_set; template using hashmap = unordered_map; using namespace __gnu_cxx; #pragma endregion // using-alias #pragma region library #ifndef modint_hpp #define modint_hpp #include #include template class modint { int val; public: static constexpr modint identity() noexcept { return 1; } constexpr modint() noexcept : val{0} {} constexpr modint(long long x) noexcept : val((x %= mod) < 0 ? mod + x : x) {} constexpr long long value() const noexcept { return val; } constexpr modint operator++(int) noexcept { modint t = *this; return ++val, t; } constexpr modint operator--(int) noexcept { modint t = *this; return --val, t; } constexpr modint &operator++() noexcept { return ++val, *this; } constexpr modint &operator--() noexcept { return --val, *this; } constexpr modint operator-() const noexcept { return modint(-val); } constexpr modint &operator+=(const modint &other) noexcept { return (val += other.val) < mod ? 0 : val -= mod, *this; } constexpr modint &operator-=(const modint &other) noexcept { return (val += mod - other.val) < mod ? 0 : val -= mod, *this; } constexpr modint &operator*=(const modint &other) noexcept { return val = (long long)val * other.val % mod, *this; } constexpr modint &operator/=(const modint &other) noexcept { return *this *= inverse(other); } constexpr modint operator+(const modint &other) const noexcept { return modint(*this) += other; } constexpr modint operator-(const modint &other) const noexcept { return modint(*this) -= other; } constexpr modint operator*(const modint &other) const noexcept { return modint(*this) *= other; } constexpr modint operator/(const modint &other) const noexcept { return modint(*this) /= other; } constexpr bool operator==(const modint &other) const noexcept { return val == other.val; } constexpr bool operator!=(const modint &other) const noexcept { return val != other.val; } constexpr bool operator!() const noexcept { return !val; } friend constexpr modint operator+(long long x, modint y) noexcept { return modint(x) + y; } friend constexpr modint operator-(long long x, modint y) noexcept { return modint(x) - y; } friend constexpr modint operator*(long long x, modint y) noexcept { return modint(x) * y; } friend constexpr modint operator/(long long x, modint y) noexcept { return modint(x) / y; } static constexpr modint inverse(const modint &other) noexcept { assert(other != 0); int a{mod}, b{other.val}, u{}, v{1}, t{}; while(b) t = a / b, a ^= b ^= (a -= t * b) ^= b, u ^= v ^= (u -= t * v) ^= v; return {u}; } static constexpr modint pow(modint other, long long e) noexcept { if(e < 0) e = e % (mod - 1) + mod - 1; modint res{1}; while(e) { if(e & 1) res *= other; other *= other, e >>= 1; } return res; } friend std::ostream &operator<<(std::ostream &os, const modint &other) noexcept { return os << other.val; } friend std::istream &operator>>(std::istream &is, modint &other) noexcept { long long val; other = {(is >> val, val)}; return is; } }; // class modint template <> class modint<2> { bool val; public: static constexpr modint identity() noexcept { return 1; } constexpr modint(bool x = false) noexcept : val{x} {} constexpr modint(int x) noexcept : val(x & 1) {} constexpr modint(long long x) noexcept : val(x & 1) {} constexpr operator bool() const noexcept { return val; } constexpr bool value() const noexcept { return val; } constexpr modint &operator+=(const modint &other) noexcept { return val ^= other.val, *this; } constexpr modint &operator-=(const modint &other) noexcept { return val ^= other.val, *this; } constexpr modint &operator*=(const modint &other) noexcept { return val &= other.val, *this; } constexpr modint &operator/=(const modint &other) noexcept { assert(other.val); return *this; } constexpr modint operator!() const noexcept { return !val; } constexpr modint operator-() const noexcept { return *this; } constexpr modint operator+(const modint &other) const noexcept { return val != other.val; } constexpr modint operator-(const modint &other) const noexcept { return val != other.val; } constexpr modint operator*(const modint &other) const noexcept { return val && other.val; } constexpr modint operator/(const modint &other) const noexcept { assert(other.val); return *this; } constexpr bool operator==(const modint &other) const noexcept { return val == other.val; } constexpr bool operator!=(const modint &other) const noexcept { return val != other.val; } friend constexpr modint operator+(long long x, modint y) noexcept { return x & 1 ? !y : y; } friend constexpr modint operator-(long long x, modint y) noexcept { return x & 1 ? !y : y; } friend constexpr modint operator*(long long x, modint y) noexcept { return x & 1 ? y : modint<2>{0}; } friend constexpr modint operator/(long long x, modint y) noexcept { assert(y.val); return x & 1 ? y : modint<2>{0}; } friend std::ostream &operator<<(std::ostream &os, const modint &other) noexcept { return os << other.val; } friend std::istream &operator>>(std::istream &is, modint &other) noexcept { long long val; other.val = (is >> val, val & 1); return is; } }; // class modint specialization #endif // modint_hpp #pragma endregion // library #pragma region main-code struct solver; template void main_(); int main() { main_(); } template void main_() { unsigned t = 1; #ifdef LOCAL t = 1; #endif // t = -1; // infinite loop // cin >> t; // case number given while(t--) solver(); } struct solver { solver() { using mint=modint<(int)1e9+7>; int n,k; cin>>n>>k; vector> T(n); for(int i=1; i>u>>v; --u,--v; T[u].emplace_back(v); T[v].emplace_back(u); } vector dp(n,vector(k,1)); make_recursive( [&](auto dfs, int now, int pre)->void { if(~pre) { T[now].erase(find(__all(T[now]),pre)); } for(int to : T[now]) { dfs(to, now); mint acc=0; for(int i=0; i anc)->void { // add to ans if(roo) { for(int j=0; j(k,1); } else { mint acc=0; for(int j=0; j(k,1)); for(int i=0; i<(int)T[now].size(); ++i) { int to=T[now][i]; mint acc=0; for(int j=0; j prod(k,1); for(int i=T[now].size(); i--; ) { int to=T[now][i]; vector nanc(anc); for(int j=0; j(k,1)); cout << ans << "\n"; } }; #pragma endregion // main-code