adding two sum to python

Author: Karthikeyan Sadayamuthu

python/array/1_two_sum.py

@@ -0,0 +1,43 @@
+"""
+Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
+
+You may assume that each input would have exactly one solution, and you may not use the same element twice.
+
+You can return the answer in any order.
+
+Example 1:
+
+Input: nums = [2,7,11,15], target = 9
+Output: [0,1]
+Output: Because nums[0] + nums[1] == 9, we return [0, 1].
+Example 2:
+
+Input: nums = [3,2,4], target = 6
+Output: [1,2]
+Example 3:
+
+Input: nums = [3,3], target = 6
+Output: [0,1]
+
+Constraints:
+2 <= nums.length <= 104
+-109 <= nums[i] <= 109
+-109 <= target <= 109
+Only one valid answer exists.
+Follow-up: Can you come up with an algorithm that is less than O(n2) time complexity?
+
+"""
+
+class Solution:
+    def twoSum(self, nums: list[int], target: int) -> list[int]:
+        # 2,7,11,15 target 9
+        lookup = {}
+        for count, num in enumerate(nums):
+            if target - num in lookup:
+                return lookup[target-num], count
+            lookup[num]=count
+
+
+if __name__ == "__manin__":
+    solution = Solution()
+    print(solution.twoSum([2,7,11,15], 9))