[Python] iterator & generator
iterator 有__next__()以取得 iterator 的下一個item 有__iter__()：return self generator 屬於 iterator，但反之則不成立 使用yield表達式實作__next__()
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Leetcode # 784. Letter Case Permutation
https://leetcode.com/problems/letter-case-permutation/ Solution Time Complexity = Space Complexity = O(len(s) * 2 ^ len(s)) class Solution: def letterCasePermutation(self, s: str) -> List[str]: f = ...
Brute-Force 暴力法/窮舉法｜Backtracking 回溯法
- 2022.07.18
- Backtracking Brute-Force Recursion
Brute-Force（暴力法 / 窮舉法） 列出所有可能的解答候選，再保留那些通過驗證的解答候選 例題 Backtracking（回溯法） Brute-Force 的一種 嘗試分步的解決問題 當現在這一步不符合條件時 ⇒ 退回上一步 經常使用遞迴 (recursion) 來實現 backtracking Difference with Dynamic Programing backtrackin ...
Leetcode # 977. Squares of a Sorted Array
- 2022.07.18
- ★ Easy LeetCode Two Pointers
https://leetcode.com/problems/squares-of-a-sorted-array/ First Solution 注意 nums 僅有負數的場合！ Time Complexity: O(len(nums)) Space Complexity: O(1) (The input and output generally do not count towards the s ...
Leetcode # 35. Search Insert Position
- 2022.07.18
- Binary Method / Divide and Conquer LeetCode
https://leetcode.com/problems/search-insert-position/ Solution Time Complexity: O(log(len(nums))) Space Complexity: O(1) class Solution: def searchInsert(self, nums: List[int], target: int) -> int: ...
聲樂課 2022/07/09
- 2022.07.14
- 聲樂
發聲練習1 肩膀環繞至後方 兩掌互推並與胸口保持一段不小的距離， 雙臂將肋骨往左右撐開 下半身箭步（一前一後）深蹲 隨著發聲慢慢更下沉 發聲練習2 肩膀環繞至後方， 雙手向前伸但不往上，使胸口向內縮 背部肩胛骨向外綣起 雙手做抱蛋狀 雙腳與肩同寬 足弓成弓狀，腳趾與腳跟穩穩抓住地面 屁股向後，尾椎至頭部呈一直線
Leetcode # 217. Contains Duplicate
- 2022.07.06
- Hash Table LeetCode Sorting
https://leetcode.com/problems/contains-duplicate/ Solution Sorting Time Complexity: O(n * log(n)) Space Complexity: O(1) with heap sort Worst case space complexity is O(n) and best case O(1) with sort ...
Leetcode # 278. First Bad Version
- 2022.07.06
- Binary Method / Divide and Conquer LeetCode
https://leetcode.com/problems/first-bad-version/ Solution Time Complexity: O(log(n)) Space Complexity: O(1) class Solution: def firstBadVersion(self, n: int) -> int: if isBadVersion(1): return 1 go ...
Leetcode # 48. Rotate Image
- 2022.07.05
- LeetCode
https://leetcode.com/problems/rotate-image/ Solution Time Complexity: O(M) Space Complexity: O(1) class Solution: def rotate(self, matrix: List[List[int]]) -> None: """ Do not return anything, modify ...
Leetcode # 31. Next Permutation
- 2022.07.05
- LeetCode
https://leetcode.com/problems/next-permutation/ Solution Step. 1 由最尾端找起，找到第一個下降的點 nums[i] Step.2 如果 nums[i] 存在，則和 nums[j] 交換 $$\mathop{\arg\min}_{j > i}{\{nums[j]\,|\,nums[j]>nums[i]\}}$$ Step.3 ...
