Refactor has_pair_with_sum function to improve efficiency and update documentation

Author: mervereis

Sprint-1/Python/has_pair_with_sum/has_pair_with_sum.py

@@ -1,18 +1,27 @@
-from typing import List, TypeVar
+def has_pair_with_sum(numbers, target_sum):
 
-Number = TypeVar("Number", int, float)
+    seen = set()
 
+    for number in numbers:
+        complement = target_sum - number
 
-def has_pair_with_sum(numbers: List[Number], target_sum: Number) -> bool:
-    """
-    Find if there is a pair of numbers that sum to a target value.
+        if complement in seen:
+            return True
+
+        seen.add(number)
 
-    Time Complexity:
-    Space Complexity:
-    Optimal time complexity:
-    """
-    for i in range(len(numbers)):
-        for j in range(i + 1, len(numbers)):
-            if numbers[i] + numbers[j] == target_sum:
-                return True
     return False
+
+
+print(has_pair_with_sum([2, 4, 6, 8], 10))
+# True
+
+print(has_pair_with_sum([1, 2, 3], 10))
+# False
+"""
+Find if there is a pair of numbers that sum to a target value.
+
+Time Complexity: O(n²)
+Space Complexity: O(1)
+Optimal Time Complexity: O(n)
+"""