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Generate ParenthesesGiven n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1:Input: n = 3Output: ["((()))","(()())","(())()","()(())","()()()"]Example 2:Input: n = 1Output: ["()"] Constraints:1 class Solution: def generateParenthesis(self, n: int) -> List[str]: def dfs(left, right, s) : if len(s) == n * 2 : ..

Single NumberGiven a non-empty array of integers nums, every element appears twice except for one. Find that single one.You must implement a solution with a linear runtime complexity and use only constant extra space. Example 1:Input: nums = [2,2,1]Output: 1Example 2:Input: nums = [4,1,2,1,2]Output: 4Example 3:Input: nums = [1]Output: 1 Constraints:1 4-3 * 104 4Each element in the array appears ..