[LeetCode] Two Sum

two_sum.py

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+'''
+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]
+Explanation: 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]
+'''
+
+def two_sum(nums, target):
+    num_indices = {}
+    for i, num in enumerate(nums):
+        complement = target - num
+        if complement in num_indices:
+            return [num_indices[complement], i]
+        num_indices[num] = i
+
+# Example 1:
+nums1 = [2, 7, 11, 15]
+target1 = 9
+result1 = two_sum(nums1, target1)
+print(result1)  # Output: [0, 1]
+
+# Example 2:
+nums2 = [3, 2, 4]
+target2 = 6
+result2 = two_sum(nums2, target2)
+print(result2)  # Output: [1, 2]
+
+# Example 3:
+nums3 = [3, 3]
+target3 = 6
+result3 = two_sum(nums3, target3)
+print(result3)  # Output: [0, 1]
+
+