class Solution: def minCost(self, nums1: list[int], nums2: list[int]) -> int: freq1 = collections.Counter(nums1) freq2 = collections.Counter(nums2) freq = freq1 + freq2 for k, v in freq.items(): if v % 2 != 0: return -1 count = 0 for num in freq: target = freq[num] // 2 if freq1[num] > target: ..

Input: nums = [3,6,2,8]Output: 5from left, check maximum value and at each location, calculate GCD with the maximum value and the current value.then sort the GCDsand from each outside, pick the two outside values and calculate GCD, and repeat it until no items left.import mathclass Solution: def gcdSum(self, nums: list[int]) -> int: mx = float('-inf') gcds = [] for num in..

Input: nums = [3,4,2,5,4,6]Output: 2class Solution: def firstUniqueEven(self, nums: list[int]) -> int: freq = collections.defaultdict(int) removes = set() evens = [] for i, num in enumerate(nums): if num % 2 == 0: freq[num] += 1 evens += num, if freq[num] > 1: removes.add(num) for remove in r..

n = 1002 -> 1,000 1,001 1,002 -> return 3class Solution: def countCommas(self, n: int) -> int: cur = n res = 0 bounds = [1_000, 1_000_000, 1_000_000_000, 1_000_000_000_000, 1_000_000_000_000_000] for i, bottom in enumerate(bounds): if cur

class Solution: def countCommas(self, n: int) -> int: if n

class Solution: def longestUnivaluePath(self, root: Optional[TreeNode]) -> int: mx = 1 def dfs(node): nonlocal mx if not node: return 0, None l_len, l_val = dfs(node.left) r_len, r_val = dfs(node.right) if node.left and node.left.val != node.val: l_len = 0 if node.right and node.right..