import heapq

def dijkstra(adj_list, start):
    dist = {v: float('inf') for v in adj_list}
    dist[start] = 0
    heap = [(0, start)]
    while heap:
        d, u = heapq.heappop(heap)
        if d > dist[u]:
            continue
        for v, w in adj_list[u]:
            if d + w < dist[v]:
                dist[v] = d + w
                heapq.heappush(heap, (dist[v], v))
    return dist

def calculate_distances(adj_list):
    dist_sum = 0
    for i in range(len(adj_list)):
        dist = dijkstra(adj_list, i)
        for j in range(i+1, len(adj_list)):
            dist_sum += dist[j]
    return dist_sum

def calculate_new_distances(adj_list, w, e, a, b):
    w_dist = dijkstra(adj_list, a)
    e_dist = dijkstra(adj_list, w + b)
    new_dist_sum = 0
    for i in range(w):
        for j in range(e):
            if i == a-1 and j == b-1:
                continue
            if i == a-1:
                dist = e_dist[w+j]
            elif j == b-1:
                dist = w_dist[i]
            else:
                dist = w_dist[i] + e_dist[w+j] + 1
            new_dist_sum += dist
    return new_dist_sum

T = int(input())
for t in range(1, T+1):
    W, E, C = map(int, input().split())
    w_connections = [[] for _ in range(W)]
    for i, x in enumerate(map(int, input().split())):
        w_connections[i].append((x-1, 1))
        w_connections[x-1].append((i, 1))
    e_connections = [[] for _ in range(E)]
    for j, f in enumerate(map(int, input().split())):
        e_connections[j].append((f-1, 1))
        e_connections[f-1].append((j, 1))
    dist_sum = calculate_distances(w_connections) + calculate_distances(e_connections)
    results = []
    for _ in range(C):
        a, b = map(int, input().split())
        new_dist_sum = calculate_new_distances(w_connections + e_connections, W, E, a-1, b-1)
        avg_dist = new_dist_sum / ((