CCO '00 P1 - Subsets

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Points: 10
Time limit: 2.0s
Memory limit: 64M

Problem type

Canadian Computing Competition: 2000 Stage 2, Day 1, Problem 1

In this problem, you will write a program to find the minimal solution to a set of set inequalities. A set inequality has the format X contains S where X may be any set name and S may be a set name or set element. If S is a set name the inequality means that X is a superset or equal to S. If S is an element the inequality means that X contains S. Sets are named A-Z and contain elements from a-z.

The first line of input specifies the number of set inequalities (N). The next N lines each contain one set inequality. For each set name that appears in the input, your program must determine its minimal set: the smallest set of elements that the name must take in order that all of the inequalities hold. Output, in alphabetical order, each set name followed its minimal set, with the elements in alphabetical order, in the format shown below.

Sample Input

A contains B
A contains c
B contains d
F contains A
F contains z
X contains Y
Y contains X
X contains x
Q contains R

Sample Output

A = {c,d}
B = {d}
F = {c,d,z}
Q = {}
R = {}
X = {x}
Y = {x}


  • 1
    Plasmatic  commented on Aug. 8, 2018, 7:42 p.m. edited

    What is the maximum of N in this question?

    edit: The maximum of N ended up being irrelavent in my solution anyway :p

  • 8
    max  commented on Feb. 14, 2018, 12:06 a.m.

    When I submit my code in python2, it only scores 4/5, however, when I submit the same code in pypy2, I receive AC. If this isn't odd enough, the versions of python are both 2.7.13

    Could someone please tell me what is going on?

  • 0
    Jeffmagma  commented on Oct. 24, 2017, 5:46 p.m.

    Is my TLE for the last case because of an infinite loop or is my algorithm too slow?

  • 4
    println_hi_  commented on May 4, 2017, 5:20 a.m.

    Is it guaranteed the sets won't be cyclic? i.e; if A contains B can B contain A

  • -16
    TypicalToxic  commented on April 5, 2017, 12:05 p.m.

  • 0
    P234rex  commented on April 4, 2017, 4:01 p.m.

    When will judging be available for this problem?

    • 0
      Kirito  commented on April 4, 2017, 10:56 p.m.

      Judges are back up.