Updated README.md. Added dev-requirements.txt, __init__.py.

README.md

+Zerosumset
+==========
 
+Example
+-------
+```python
+>>> import zerosumset
+
+>>> elems = [-7, -3, -2, 9000, 5, 8]
+
+>>> zerosumset.zerosumset(elems)
+[-3, -2, 5]
+
+>>> zerosumset.zerosumset(3, 1, 10, -4)
+[3, 1, -4]
+```
+
+For developers
+--------------
+
+List of required packages in [dev-requirements.txt](dev-requirements.txt)
+
+Project
+-------
+
+[THD](https://th-deg.de)
+
+Licence
+-------
+
+[MIT](LICENSE)

dev-requirements.txt

+pdoc
+pytest
+hypothesis
\ No newline at end of file

zerosumset/__init__.py

+
+from z3 import *
+
+elems = [-7, -3, -2, 9000, 5, 8]
+
+def zerosumset(elems):
+
+
+    n = len(elems)
+
+    # Symbolic variables: is_in[i] is 1, if element i is in the zero sum subset, 0 otherwise
+    is_in = [Int(f"{i}") for i in range(n)]
+
+    # Create Z3 solver
+    s = Solver()
+
+    # First constraint: is_in[i] is either 0 or 1
+    for i in range(n):
+        s.add(Or(is_in[i] == 0, is_in[i] == 1))
+
+    # Second constraint: at least one element should be in the zero sum subset:
+    s.add(Sum(is_in) > 0)
+
+    # Third constraint: the sum of the elements in the zero sum subset should be zero:
+    s.add(Sum([elems[i] * is_in[i] for i in range(n)]) == 0)
+
+    # Check satisfiability and print solution if found
+    if s.check() == sat:
+        print([elems[i] for i in range(n) if s.model().eval(is_in[i], model_completion=True) == 1])
+    else:
+        print("Unsatisfiable!")
\ No newline at end of file