C - 403 Forbidden https://atcoder.jp/contests/abc403/tasks/abc403_c

abc403_c.py

N, M, Q = map(int, input().split())
contests = [set() for _ in range(N)]
all_ok = [False] * N
for _ in range(Q):
    t, *query = map(int, input().split())
    if t == 1:
        x, y = query[0] - 1, query[1] - 1
        contests[x].add(y)
    elif t == 2:
        x = query[0] - 1
        all_ok[x] = True
    else:
        x, y = query[0] - 1, query[1] - 1
        if all_ok[x]:
            print("Yes")
        else:
            print("Yes" if y in contests[x] else "No")