def solve_case(W, E, existing_western_connections, existing_eastern_connections, overpass_connections):
    # Initialize adjacency matrix
    INF = 10**18
    adj = [[INF]*(W+E) for _ in range(W+E)]
    for i in range(W-1):
        adj[i][i+1] = 1
        adj[i+1][i] = 1
        adj[i][W+E-1] = INF
        adj[W+E-1][i] = INF
    for i in range(E-1):
        adj[W+i][W+i+1] = 1
        adj[W+i+1][W+i] = 1
        adj[i+W][W+E-1] = INF
        adj[W+E-1][i+W] = INF
    for i in range(W-1):
        j = existing_western_connections[i]-1
        adj[i][j] = 1
        adj[j][i] = 1
    for i in range(E-1):
        j = existing_eastern_connections[i]-1
        adj[W+i][W+j] = 1
        adj[W+j][W+i] = 1

    # Calculate initial average distance
    total_distance = 0
    for i in range(W+E):
        for j in range(i+1, W+E):
            total_distance += adj[i][j]
    initial_average_distance = total_distance / ((W+E)*(W+E-1)/2)

    # Calculate average distance for each option
    result = []
    for west, east in overpass_connections:
        i, j = west-1, W+east-1
        # Add overpass connection
        adj[i][j] = 1
        adj[j][i] = 1
        # Run Floyd-Warshall algorithm
        for k in range(W+E):
            for i in range(W+E):
                for j in range(W+E):
                    adj[i][j] = min(adj[i][j], adj[i][k]+adj[k][j])
        # Calculate average distance
        total_distance = 0
        for i in range(W+E):
            for j in range(i+1, W+E):
                total_distance += adj[i][j]
        average_distance = total_distance / ((W+E)*(W+E-1)/2)
        result.append(average_distance)
        # Remove overpass connection
        adj[i][j] = INF
        adj[j][i] = INF

    return result


# Read input
T = int(input())
for case in range(1, T+1):
    W, E, C = map(int, input().split())
    existing_western_connections = list(map(int, input().split()))
    existing_eastern