https://leetcode.com/problems/two-sum/s

twoSum.py

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        sorted_nums = sorted(nums)
        res = []
        
        left = 0;
        right = len(sorted_nums) - 1
        
        while right >= left:
            current_sum = sorted_nums[left] + sorted_nums[right]
            if current_sum == target:
                break
            elif current_sum > target:
                right -= 1
            else:
                left += 1
        for i in range(len(nums)):
            if nums[i] == sorted_nums[left]:
                res.append(i)
                break
        for j in reversed(range(len(nums))):
            print(j)
            if nums[j] == sorted_nums[right]:
                res.append(j)
                break
        return res

twoSum2.py

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        
        seen = {}
        
        for i in range(len(nums)):
            expected_num = target - nums[i]
            
            if expected_num in seen:
                return [seen[expected_num], i]
            else:
                seen[nums[i]] = i
                
        return []