add solution to Project Euler problem 206

Author: nico

project_euler/problem_206/__init__.py

@@ -0,0 +1,30 @@
+"""
+Problem Statement:
+Find the unique positive integer whose square has the form 1_2_3_4_5_6_7_8_9_0,
+where each “_” is a single digit.
+"""
+
+from itertools import product
+
+
+def solution() -> int:
+    """
+    Returns the positive integer whose square has the form 1_2_3_4_5_6_7_8_9_0 using
+    itertool product to generate all possible digit combinations 0...9 for the nine "_"
+    to fill.
+
+    >>> solution()
+    1389019170
+    """
+
+    for p in product("0123456789"[::-1], repeat=9):
+        squared = int("1{}2{}3{}4{}5{}6{}7{}8{}9{}0".format(*p))
+
+        root_integer = int(squared ** 0.5)
+
+        if root_integer ** 2 == squared:
+            return root_integer
+
+
+if __name__ == "__main__":
+    print(solution())