nikiforosbotis / StableMarriage

Implementation of the Gale-Shapley algorithm in Python

StableMarriage

This code contains a Python script with the implementation of the Gale-Shapley algorithm

In the problem of Stable Marriage we are looking for a stable matching between men and women having as input the preferences of both males.

In our case, the preferences are given through JSON files:

{
  "men_rankings": {
    "abe": ["cat", "bea", "ada"],
    "bob": ["ada", "cat", "bea"],
    "cal": ["ada", "bea", "cat"]
  },

  "women_rankings": {
    "ada": ["abe", "cal", "bob"],
    "bea": ["bob", "abe", "cal"],
    "cat": ["cal", "abe", "bob"]
  }
}

The program's output is also given as a JSON file:

{"abe": "cat", "bob": "bea", "cal": "ada"}

If we start tackling the problem from men's part, the solution that is produced is optimized for them (as the above). On the other hand, if we tackle it from the women's part, the solution should be optimized for the women:

{"ada": "abe", "bea": "bob", "cat": "cal"}

The program can be run with the following ways:

• python3 stable_marriage.py -m <input_filename>, which outputs the solution that is optimized for the men. The script produces a JSON representation of the solution: { "man": "woman", "another_man": "another_woman", ...}.
• python3 stable_marriage.py -m <input_filename> -o <output_filename>, which also outputs the solution that is optimized for the men. The script is saved on a file named output_filename.
• python3 stable_marriage.py -w <input_filename>, which outputs the solution that is optimized for the women. The script produces a JSON representation of the solution: { "woman": "man", "another_woman": "another_man", ...}.
• python3 stable_marriage.py -w <input_filename> -o <output_filename>, which also outputs the solution that is optimized for the women. The script is saved on a file named output_filename.

Example files for input-output:

• example_1.json, optimized solution for men example_1_m.json, optimized solution for women example_1_w.json.
• example_2.json, optimized solution for men example_2_m.json, optimized solution for women example_2_w.json.
• example_3.json, optimized solution for men example_3_m.json, optimized solution for women example_3_w.json.

The full program's description (in Greek) can be found here.