#line 1 "library-cpp/other/template.hpp" // clang-format off #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using uint = unsigned int; using ll = long long; using ull = unsigned long long; using i128 = __int128_t; using ld = long double; using pii = pair; using pll = pair; template using maxheap = priority_queue; template using minheap = priority_queue, greater>; template using vec = vector; template using vvec = vector>; #define OVERLOAD_REP(_1, _2, _3, name, ...) name #define REP0(n) for (auto minato = decay_t{}; minato < (n); ++minato) #define REP1(i, n) for (auto i = decay_t{}; (i) < (n); (i)++) #define REP2(i, l, r) for (auto i = (l); (i) < (r); (i)++) #define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1, REP0)(__VA_ARGS__) #define OVERLOAD_RREP(_1, _2, _3, name, ...) name #define RREP1(i, n) for (auto i = (n) - 1; (i) >= decay_t{}; (i)--) #define RREP2(i, l, r) for (auto i = (r) - 1; (i) >= (l); (i)--) #define rrep(...) OVERLOAD_RREP(__VA_ARGS__, RREP2, RREP1)(__VA_ARGS__) #define all(x) begin(x), end(x) template int SZ(const Container& v) { return int(v.size()); } template void UNIQUE(vector& v) { v.erase(unique(v.begin(), v.end()), v.end()); } template T MAX(const vector& v) { return *max_element(v.begin(), v.end()); } template T MIN(const vector& v) { return *min_element(v.begin(), v.end()); } template T SUM(const vector& v) { return accumulate(v.begin(), v.end(), T(0)); } template T ABS(T x) { return max(x, -x); } template bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; } int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); } int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); } int popcount(ull x) { return __builtin_popcountll(x); } int kthbit(ull x, int k) { return (x >> k) & 1; } constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; } template void rearrange(const vector& id) { (void)id; } template void rearrange_exec(const vector& id, vector& v) { vector w(v.size()); for (size_t i = 0; i < id.size(); i++) { w[i] = v[id[i]]; } v.swap(w); } template void rearrange(const vector& id, Head& a, Tail& ...tail) { rearrange_exec(id, a); rearrange(id, tail...); } istream& operator>>(istream& is, __int128_t& x) { x = 0; string s; is >> s; int n = int(s.size()), it = 0; if (s[0] == '-') it++; for (; it < n; it++) x = (x * 10 + s[it] - '0'); if (s[0] == '-') x = -x; return is; } ostream& operator<<(ostream& os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; deque deq; while (x) deq.emplace_front(x % 10), x /= 10; for (int e : deq) os << e; return os; } template vector &operator++(vector& v) { for (auto& e : v) { e++; } return v;} template vector operator++(vector& v, int) { auto res = v; for (auto& e : v) { e++; } return res; } template vector &operator--(vector& v) { for (auto& e : v) { e--; } return v; } template vector operator--(vector& v, int) { auto res = v; for (auto& e : v) { e--; } return res; } template pair operator-(const pair& x) { return pair(-x.first, -x.second); } template pair operator-(const pair& x, const pair& y) { return pair(x.first - y.first, x.second - y.second); } template pair operator+(const pair& x, const pair& y) { return pair(x.first + y.first, x.second + y.second); } template pair operator+=(pair& l, const pair& r) { return l = l + r; } template pair operator-=(pair& l, const pair& r) { return l = l - r; } constexpr char ln = '\n'; const string YESNO[2] = {"NO", "YES"}; const string YesNo[2] = {"No", "Yes"}; void YES(bool t = true) { cout << YESNO[t] << "\n"; } void NO(bool t = 1) { YES(!t); } void Yes(bool t = true) { cout << YesNo[t] << "\n"; } void No(bool t = 1) { Yes(!t); } template void drop(T x) { cout << x << "\n"; exit(0); } #define INT(...) \ int __VA_ARGS__; \ IN(__VA_ARGS__) #define LL(...) \ ll __VA_ARGS__; \ IN(__VA_ARGS__) #define STR(...) \ string __VA_ARGS__; \ IN(__VA_ARGS__) #define CHR(...) \ char __VA_ARGS__; \ IN(__VA_ARGS__) #define LDB(...) \ long double __VA_ARGS__; \ IN(__VA_ARGS__) #define VEC(type, name, size) \ vector name(size); \ IN(name) #define VEC2(type, name1, name2, size) \ vector name1(size), name2(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i]) #define VEC3(type, name1, name2, name3, size) \ vector name1(size), name2(size), name3(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i], name3[i]) #define VEC4(type, name1, name2, name3, name4, size) \ vector name1(size), name2(size), name3(size), name4(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i], name3[i], name4[i]); #define VV(type, name, N, M) \ vector> name(N, vector(M)); \ IN(name) template void scan(T& a) { cin >> a; } template void scan(vector& a) { for (auto& i : a) scan(i); } void IN() {} template void IN(Head& head, Tail&... tail) { scan(head); IN(tail...); } void print() { cout << "\n"; } template void print(const vector& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); } template void print(const T& x, const Args& ... args) { cout << x; if (sizeof...(Args)) cout << " "; print(args...); } #ifdef MINATO_LOCAL template ostream& operator<<(ostream& os, pair p) { return os << "(" << p.first << ", " << p.second << ")"; } template void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; } template void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get(t); debug_tuple(os, t); } template ostream& operator<<(ostream& os, tuple t) { os << "("; debug_tuple<0, tuple, Args...>(os, t); return os << ")"; } string debug_delim(int& i) { return i++ == 0 ? "" : ", "; } #define debug_embrace(x) { int i = 0; os << "{"; { x } return os << "}"; } template ostream& operator<<(ostream& os, vector v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, array a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template enable_if_t>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, set s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, map mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, multiset s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) } template ostream& operator<<(ostream& os, deque q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, priority_queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } template ostream& operator<<(ostream& os, priority_queue, greater> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } void debug_out() { cerr << endl; } template void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); } #define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__) #else #define debug(...) (void(0)) #endif /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // clang-format on #line 2 "library-cpp/datastructure/UnionFind.hpp" /** * 高速、省メモリなシンプルな UnionFind を使いたい場合、atcoder::dsu を使う。 */ struct UnionFind { private: int n, group_number; vector parent_or_size, nex; public: UnionFind() : n(0), group_number(0) { } UnionFind(int n) : n(n), group_number(n), parent_or_size(n, -1), nex(n) { iota(nex.begin(), nex.end(), 0); } int size() const { return n; } /** * 連結成分の個数を取得する。 */ int count() const { return group_number; } bool merge(int x, int y) { assert(0 <= x and x < n); assert(0 <= y and y < n); x = root_(x); y = root_(y); if (x == y) return false; if (parent_or_size[x] > parent_or_size[y]) swap(x, y); parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; swap(nex[x], nex[y]); group_number--; return true; } /** * @param f void f(int parent, int child) * マージする際の処理を行う関数を渡す。 */ template bool merge(int x, int y, const F& f) { assert(0 <= x and x < n); assert(0 <= y and y < n); x = root_(x); y = root_(y); if (x == y) return false; if (parent_or_size[x] > parent_or_size[y]) swap(x, y); f(x, y); parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; swap(nex[x], nex[y]); group_number--; return true; } bool same(int x, int y) { assert(0 <= x and x < n); assert(0 <= y and y < n); return root_(x) == root_(y); } int root(int x) { assert(0 <= x and x < n); return root_(x); } /** * 頂点 x の属する連結成分のサイズを返す。 */ int size(int x) { assert(0 <= x and x < n); return -parent_or_size[root_(x)]; } /** * 頂点 x の属する連結成分の代表元を返す。 * root(x) と同じ。 */ int operator[](int x) { assert(0 <= x and x < n); return root_(x); } vector> groups() { vector leader_buf(n), group_size(n); for (int i = 0; i < n; i++) { leader_buf[i] = root(i); group_size[leader_buf[i]]++; } vector> result(n); for (int i = 0; i < n; i++) { result[i].reserve(group_size[i]); } for (int i = 0; i < n; i++) { result[leader_buf[i]].push_back(i); } result.erase(remove_if(result.begin(), result.end(), [&](const vector& v) { return v.empty(); }), result.end()); return result; } /** * 頂点 x の属する連結成分の頂点番号のリストを返す。 * O(size(x)) */ vector group(int x) const { assert(0 <= x and x < n); vector ret; int v = x; do { ret.emplace_back(v); v = nex[v]; } while (v != x); return ret; } private: int root_(int x) { if (parent_or_size[x] < 0) return x; return parent_or_size[x] = root_(parent_or_size[x]); } }; #line 3 "C.cpp" void solve() { INT(N, Q); VEC(int, P, N); UnionFind uf(N); rep(i, N) { if (P[i] == -1) continue; uf.merge(i, P[i] - 1); } rep(Q) { INT(a, b); a--; b--; Yes(uf.same(a, b)); } } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); int T = 1; // cin >> T; for (int test_case = 1; test_case <= T; test_case++) { // debug(test_case); solve(); } }