#pragma region Macros #include #define rep(i, n) for(int(i) = 0; (i) < (n); (i)++) #define rrep(i, n) for(int(i) = (n)-1; (i) >= 0; (i)--) #define FOR(i, m, n) for(int(i) = (m); (i) < (n); (i)++) #define ROF(i, m, n) for(int(i) = (n)-1; (i) >= (m); (i)--) #define ALL(v) (v).begin(), (v).end() #define LLA(v) (v).rbegin(), (v).rend() #define SZ(v) (int)(v).size() #define INT(...) \ int __VA_ARGS__; \ read(__VA_ARGS__) #define LL(...) \ ll __VA_ARGS__; \ read(__VA_ARGS__) #define DOUBLE(...) \ double __VA_ARGS__; \ read(__VA_ARGS__) #define CHAR(...) \ char __VA_ARGS__; \ read(__VA_ARGS__) #define STRING(...) \ string __VA_ARGS__; \ read(__VA_ARGS__) #define VEC(type, name, size) \ vector name(size); \ read(name) #define VEC2(type, name, height, width) \ vector> name(height, vector(width)); \ read(name) #define DVEC(type, name1, name2, size) \ vector name1(size), name2(size); \ read(name1, name2) #define TVEC(type, name1, name2, name3, size) \ vector name1(size), name2(size), name3(size); \ read(name1, name2, name3) using namespace std; using ll = long long; using pii = pair; using pll = pair; const int INF = 1 << 30; const ll LINF = 1LL << 60; const int MOD = 1e9 + 7; const char newl = '\n'; const int dx[] = {1, 0, -1, 0}; const int dy[] = {0, 1, 0, -1}; template inline bool between(T x, T l, T r) { return l <= x && x < r; } template inline vector make_vec(size_t a, T val) { return vector(a, val); } template inline auto make_vec(size_t a, Ts... ts) { return vector(a, make_vec(ts...)); } void read() {} template inline void read(T &a) { cin >> a; } template inline void read(pair &p) { read(p.first), read(p.second); } template inline void read(vector &v) { for(auto &&a : v) read(a); } template inline void read(vector &a, vector &b) { for(int i = 0; i < a.size(); i++) { read(a[i]); read(b[i]); } } template inline void read(vector &a, vector &b, vector &c) { for(int i = 0; i < a.size(); i++) { read(a[i]); read(b[i]); read(c[i]); } } template inline void read(Head &head, Tail &...tail) { read(head), read(tail...); } template void _write(const T &a) { cout << a; } template void _write(const std::pair &a) { cout << a.first << ' ' << a.second; } template void write(const T &a) { _write(a); cout << newl; } template void write(const vector &a) { for(int i = 0; i < a.size(); i++) { _write(a[i]); cout << (i + 1 == a.size() ? newl : ' '); } } template void write(const Head &head, const Tail &...tail) { _write(head); cout << ' '; write(tail...); } template void writel(const T &a) { cout << a << '\n'; } template void writel(const vector &a) { for(int i = 0; i < a.size(); i++) { _write(a[i]); cout << newl; } } template void writel(const Head &head, const Tail &...tail) { _write(head); cout << newl; write(tail...); } template void _debug(const T &a) { cerr << a; } template void _debug(const std::pair &a) { cerr << a.first << ' ' << a.second; } template void debug(const T &a) { _debug(a); cerr << newl; } template void debug(const vector &a) { for(int i = 0; i < a.size(); i++) { _debug(a[i]); cerr << (i + 1 == a.size() ? newl : ' '); } } template void debug(const Head &head, const Tail &...tail) { _debug(head); cerr << ' '; debug(tail...); } template void debugl(const T &a) { cerr << a << '\n'; } template void debugl(const vector &a) { for(int i = 0; i < a.size(); i++) { _debug(a[i]); cerr << newl; } } template void debugl(const Head &head, const Tail &...tail) { _debug(head); cerr << newl; debug(tail...); } template auto sum(const vector &a) { return accumulate(ALL(a), T(0)); } template auto min(const vector &a) { return *min_element(ALL(a)); } template auto max(const vector &a) { return *max_element(ALL(a)); } template void msort(vector &a, vector &b) { assert(a.size() == b.size()); vector> ab(a.size()); for(int i = 0; i < a.size(); i++) ab[i] = {a[i], b[i]}; sort(ALL(ab)); for(int i = 0; i < a.size(); i++) { a[i] = ab[i].first; b[i] = ab[i].second; } } template void msort(vector &a, vector &b, vector &c) { assert(a.size() == b.size() && b.size() == c.size()); vector> abc(a.size()); for(int i = 0; i < a.size(); i++) abc[i] = {a[i], b[i], c[i]}; sort(ALL(abc)); for(int i = 0; i < a.size(); i++) { a[i] = get<0>(abc[i]); b[i] = get<1>(abc[i]); c[i] = get<2>(abc[i]); } } template inline bool chmax(T &a, U b) { if(a < b) { a = b; return 1; } return 0; } template inline bool chmin(T &a, U b) { if(a > b) { a = b; return 1; } return 0; } int digit(ll a) { ll ret = 0; while(a && ++ret) a /= 10; return ret; } int digit_sum(ll a) { ll ret = 0; while(a) { ret += a % 10; a /= 10; } return ret; } ll llpow(ll a, ll n) { ll ret = 1; rep(i, n) ret *= a; return ret; } inline int bsf(int v) { return __builtin_ctz(v); } // 最下位の1が下から何番目か inline int bsf(ll v) { return __builtin_ctzll(v); } inline int bsr(int v) { return 31 - __builtin_clz(v); } // 最上位の1が下から何番目か inline int bsr(ll v) { return 63 - __builtin_clzll(v); } inline int lsb(int v) { return v & -v; } // 最下位の1だけ残す inline ll lsb(ll v) { return v & -v; } inline int msb(int v) { return 1 << bsr(v); } // 最上位の1だけ残す inline ll msb(ll v) { return 1LL << bsr(v); } struct IO { IO() { ios::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(10); } } io; #pragma endregion // UnionFind struct UnionFind { vector par; vector siz; UnionFind(int N) : par(N), siz(N, 1) { for(int i = 0; i < N; i++) par[i] = i; } int root(int x) { if(par[x] == x) return x; return par[x] = root(par[x]); } void unite(int x, int y) { int rx = root(x); int ry = root(y); if(rx == ry) return; if(siz[rx] < siz[ry]) swap(rx, ry); siz[rx] += siz[ry]; par[ry] = rx; } bool same(int x, int y) { int rx = root(x); int ry = root(y); return rx == ry; } int size(int x) { return siz[root(x)]; } }; //  重み付きUnionFind template struct WeightedUnionFind { vector par; vector siz; vector diff_weight; WeightedUnionFind(int N) : par(N), siz(N, 1), diff_weight(N, T(0)) { for(int i = 0; i < N; i++) { par[i] = i; } } T weight(int x) { root(x); return diff_weight[x]; } T diff(int x, int y) { return weight(y) - weight(x); } int root(int x) { if(par[x] == x) return x; else { int r = root(par[x]); diff_weight[x] += diff_weight[par[x]]; return par[x] = r; } } void unite(int x, int y, T w) { w += weight(x), w -= weight(y); int rx = root(x); int ry = root(y); if(rx == ry) return; if(siz[rx] < siz[ry]) swap(rx, ry), w = -w; siz[rx] += siz[ry]; par[ry] = rx; diff_weight[ry] = w; } bool same(int x, int y) { int rx = root(x); int ry = root(y); return rx == ry; } int size(int x) { return siz[root(x)]; } }; void solve() { INT(n, Q); VEC(int, p, n); UnionFind uf(n); rep(i, n) { if(p[i] != -1) { uf.unite(i, p[i] - 1); } } rep(i, Q) { INT(a, b); a--, b--; write(uf.same(a, b) ? "Yes" : "No"); } } int main() { int t = 1; // cin >> t; while(t--) { solve(); } }