C++小考檢討與fibonacci費氏數列top down設計實作

C++作業遞迴函數實作fibonacci費氏數列於Colab, Leetcode Visual studio與Python版比較

C++遞迴函數與fibonacci費氏數列

C++ Py3 Sliding window速解Leetcode 2379 Minimum Recolors to Get K Consec...

C++ Py3  Sliding window速解2379  Minimum Recolors to Get K Consecutive Black Blocks

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Py3 C++算術數列算面積一行解Leetcode 2579 Count Total Number of Colored Cells

Py3 C++算術數列算面積一行解Leetcode 2579  Count Total Number of Colored Cells

利用算術數列面積公式一行解Leetcode 257

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模仿遊戲enigma納粹密碼機與cryptool2破解the code book相關密碼2

模仿遊戲enigma納粹密碼機與cryptool2破解the code book相關密碼1

C++ prefix sum Kadane Python一行解Leetcode 1749. Maximum Absolute Sum of An...

cpp prefix sum Kadane Python一行解Leetcode 1749. Maximum Absolute Sum of Any Subarray

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C++py3排列組合與binary表達解Leetcode 1415 The k th Lexicographical String of Al...

C++py3排列組合與binary表達解Leetcode 1415  The k th Lexicographical String of All Happy Strings of Length n

總共有3*2^(n-1)個happy strings要求第k個。先算(k-1)除以2^(n-1)的商q與餘數r，s[0]由q決定，s[1:n]由r決定，化r為二進位，然後簡單處理一下就得解

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C++ Py3 reverse 2pointer解Leetcode 2375 Construct Smallest Number From D...

C++ Py3 reverse 2pointer解Leetcode 2375  Construct Smallest Number From DI String

[codes on Leetcode]https://leetcode.com/problems/construct-smallest-number-from-di-string/solutions/6435240/suffix-sum-for-successive-ds-c-py3-beats-100/

C++ OOP Prefix Product解Leetcode 1352 Product of the Last K Numbers

C++ OOP Prefix Product解Leetcode 1352  Product of the Last K Numbers

Leetcode這題1352. Product of the Last K Numbers，是很好的OOP題目，除了談談class之外，還能練習一下prefix product的概念(與prefix sum類似但要小心0)

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如何在colab上撰寫C++程式

Python C++ hashmap解Leetcode 3160 Find the Number of Distinct Colors Am...

Python C++  hashmap解Leetcode 3160  Find the Number of Distinct Colors Among the Balls

嘗試2個hashmap來解決。由於實際運行，可以說，Python dict 比 C++ unordered_map 快得多

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排列組合Python解Leetcode 1726 Tuple with Same Product

本片展示如何理解這題排列組合實質內容，以及如何完成 1 行Python程式碼。

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Python C++單迴圈速解Leetcode 3105 Longest Strictly Increasing or Strictly De...

Python cpp單迴圈速解Leetcode 3105  Longest Strictly Increasing or Strictly Decreasing Subarray

用單迴圈就可解，甚至也沒有用到if, switch, tenary

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C++ UnionFind解難題Leetcdoe 827 Making A Large Island(含Py3解)

C++ UnionFind解難題Leetcdoe 827  Making A Large Island

嘗試UnionFind解決。由於該題目透過最多翻轉 1 個額外的 0 單元來詢問最大島嶼的大小；使用Size優化而不是rank。

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Python C++BFS /heap解Leetcode難題407 Trapping Rain Water II

Py3 cpp BFS /heap解Leetcode難題407 Trapping Rain Water II

解題要訣:boundary由外而內，容器採min heap，BFS走訪

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Python C++速解Leetcode迴文1400 Construct K Palindrome Strings

Python C++速解Leetcode迴文1400  Construct K Palindrome Strings

關鍵：偶數長度的回文字串中所有字母都出現偶數，奇數長度的回文字串中除了一個例外其他所有字母都出現偶數。

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The key observation: palindrome strings of even lengths have all letters even occurrences, palindrome strings of odd lengths have all letters even occurrences but except one letter with odd occurrence.

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C++ python 用Prefix Sum速解Leetcode 2270 Number of Ways to Split Array

Prefix sum這個概念，只要數學會用Sigma的，問題都不大，基本上就是partial sum。程式要寫的好，老實講該有數學概念真不能少，演算法的東西畢竟是真刀真槍的。

C++ python 用Prefix Sum速解Leetcode 2270  Number of Ways to Split Array

求分割陣列 nums 的方式數量，使得 sum(nums[0...i]) \geq sum(nums[i+1...])。

如何？計算總和sum=sum(nums)

使用loop判斷i是否滿足sum(nums[0..i])\geq sum(nums[i..])=sum-sum(nums[0..i])

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