NODES = ["in","p1","p2","p3","p4","p5","p6","p7","p8","p9","p10","p11","p12","p13","out"]

SUCCESSORS = {
    "in":  {"p1"},
    "p1":  {"p2"},
    "p2":  {"p3"},
    "p3":  {"p4"},
    "p4":  {"p5"},
    "p5":  {"p6"},
    "p6":  {"p7","out"},
    "p7":  {"p8"},
    "p8":  {"p9"},
    "p9":  {"p10","p11"},
    "p10": {"p12"},
    "p11": {"p12"},
    "p12": {"p13"},
    "p13": {"p6"},
    "out": set()
}

USE = {
    "in":  set(),
    "p1":  set(),
    "p2":  set(),
    "p3":  set(),
    "p4":  {"i","j"},
    "p5":  set(),
    "p6":  {"s"},
    "p7":  {"s"},
    "p8":  {"i","j","f"},
    "p9":  {"c"},
    "p10": {"j","c"},
    "p11": {"j","c"},
    "p12": {"j","f"},
    "p13": {"s"},
    "out": set()
}

DEF = {
    "in":  set(),
    "p1":  {"s"},
    "p2":  {"i"},
    "p3":  {"j"},
    "p4":  {"t"},
    "p5":  {"f"},
    "p6":  set(),
    "p7":  {"a"},
    "p8":  {"c"},
    "p9":  set(),
    "p10": {"j"},
    "p11": {"i"},
    "p12": {"i"},
    "p13": {"s"},
    "out": set()
}

def pretty_print(iteration, nodes, IN, OUT):
    w_v   = 6
    w_set = 32

    def fmt(s):
        return "{" + ", ".join(sorted(s)) + "}"

    print(f"\nIteration {iteration}")
    print("=" * (w_v + 2*w_set + 7))
    print(f"{'v':<{w_v}} | {'IN':<{w_set}} | {'OUT':<{w_set}}")
    print("-" * (w_v + 2*w_set + 7))

    for v in nodes:
        print(
            f"{v:<{w_v}} | "
            f"{fmt(IN[v]):<{w_set}} | "
            f"{fmt(OUT[v]):<{w_set}}"
        )

    print("=" * (w_v + 2*w_set + 7))

i = 0
IN  = {v: set() for v in NODES}
OUT = {v: set() for v in NODES}

for v in NODES:
    IN[v] = USE[v]
pretty_print(i, NODES, IN, OUT)

changed = True
while changed:
    changed = False
    i += 1

    for v in NODES:
        old_in = IN[v].copy()
        old_out = OUT[v].copy()

        OUT[v] = set().union(*(IN[s] for s in SUCCESSORS[v]))
        IN[v] = USE[v] | (OUT[v] - DEF[v])

        if IN[v] != old_in or OUT[v] != old_out:
            changed = True

    pretty_print(i, NODES, IN, OUT)