t = int(input())

for _ in range(t):
    variables = [int(_) for _ in input().split()]
    n = variables[0]
    s = variables[1]
    k = variables[2]
    closed = [int(i) for i in input().split()]
    minimum2 = minimum1 = n + 1
    if s in closed:
        for x in range(s, n):
            if x not in closed and x < minimum1:
                minimum1 = x - s
        for y in range(1, s+1):
            if x not in closed and x < minimum2:
                minimum2 = s - x
        print(min(minimum1, minimum2))
    else:
        print(0)