Problem 1 and 2

0001-two-sum/solution.py

@@ -0,0 +1,9 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        dic = {}
+        for i, val in enumerate(nums):
+            if target - val in dic:
+                return [dic[target - val], i]
+            else:
+                dic[val] = i
+        

0002-add-two-numbers/solution.py

@@ -0,0 +1,22 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def addTwoNumbers(self, l1: Optional[ListNode], l2: Optional[ListNode]) -> Optional[ListNode]:
+        i = 1
+        n1 = n2 = 0
+        while not (l1 == None and l2 == None):
+            if l1 != None:
+                n1 += (l1.val * i)
+                l1 = l1.next
+            if l2 != None:
+                n2 += (l2.val * i)
+                l2 = l2.next
+            i *= 10
+        n = None
+        for c in list(str(n1 + n2)):
+            n = ListNode(int(c), n)
+        return n
+