def resolve(): n, m, q = map(int, input().split()) edges = [[] for _ in range(n)] uf = UnionFind(n) for _ in range(m): u, v = map(lambda x: int(x) - 1, input().split()) edges[u].append(v) edges[v].append(u) uf.union(u, v) u = UnionFind(n) for v in uf.all_group_members().values(): d = {j: i for i, j in enumerate(v)} edge = [[] for _ in range(len(v))] for i, j in enumerate(v): for k in edges[j]: edge[i].append(d[k]) bridge, _ = bridge_detection(edge) for i, j in bridge: u.union(v[i], v[j]) for _ in range(q): x, y = map(lambda x: int(x) - 1, input().split()) if u.same(x, y): print("Yes") else: print("No") def bridge_detection(graph, start=0): # 橋、二重辺連結成分 import sys RECURSION_LIMIT = 10 ** 6 sys.setrecursionlimit(RECURSION_LIMIT) n = len(graph) order = [-1] * n bridges = [] cycle_graph = [set() for _ in range(n)] cnt = -1 def dfs(u, prev): nonlocal cnt cnt += 1 low_pt = order[u] = cnt for v in graph[u]: if v == prev: continue if order[v] == -1: v_low_pt = dfs(v, u) if v_low_pt > order[u]: bridges.append(tuple(sorted([u, v]))) else: cycle_graph[u].add(v) cycle_graph[v].add(u) low_pt = min(low_pt, v_low_pt) else: low_pt = min(low_pt, order[v]) cycle_graph[u].add(v) cycle_graph[v].add(u) return low_pt dfs(start, -1) return sorted(bridges), cycle_graph class UnionFind: def __init__(self, n: int) -> None: self.n = n self.parent = [-1] * n self.groups = n def find(self, x: int) -> int: if self.parent[x] < 0: return x else: p = x while self.parent[p] >= 0: p = self.parent[p] while self.parent[x] >= 0: self.parent[x], x = p, self.parent[x] return p def union(self, x: int, y: int) -> bool: x = self.find(x) y = self.find(y) if x == y: return False if self.parent[x] > self.parent[y]: x, y = y, x self.parent[x] += self.parent[y] self.parent[y] = x self.groups -= 1 return True def union_right(self, x: int, y: int) -> bool: x = self.find(x) y = self.find(y) if x == y: return False if y > x: x, y = y, x self.parent[x] += self.parent[y] self.parent[y] = x self.groups -= 1 return True def union_left(self, x: int, y: int) -> bool: x = self.find(x) y = self.find(y) if x == y: return False if x > y: x, y = y, x self.parent[x] += self.parent[y] self.parent[y] = x self.groups -= 1 return True def size(self, x: int) -> int: return -self.parent[self.find(x)] def same(self, x: int, y: int) -> bool: return self.find(x) == self.find(y) def members(self, x: int) -> list: root = self.find(x) return [i for i in range(self.n) if self.find(i) == root] def roots(self) -> list: return [i for i, x in enumerate(self.parent) if x < 0] def group_count(self) -> int: return self.groups def sizes(self) -> dict: return {i: -x for i, x in enumerate(self.parent) if x < 0} def all_group_members(self) -> dict: from collections import defaultdict d = defaultdict(list) for i in range(self.n): p = self.find(i) d[p].append(i) return d def __str__(self) -> str: return '\n'.join('{}: {}'.format(k, v) for k, v in self.all_group_members().items()) if __name__ == '__main__': resolve()