feat: [Week 03-1] solve two-sum

Author: Chaedie

two-sum/Chaedie.py

@@ -0,0 +1,21 @@
+"""
+Solution:
+    Use a hash map to store numbers and their indices
+    Iterate through the list and check if difference between target and val 
+    return the index list
+
+Time: O(n)
+Space: O(n)
+
+"""
+
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        num_map = {}  # num : index
+
+        for i, val in enumerate(nums):
+            diff = target - val
+            if diff in num_map:
+                return [num_map[diff], i]
+            num_map[val] = i