C++ Py3 hashmap與binary search解Leetcode 1865 Finding Pairs With a Certain...

C++ Py3 hashmap與binary search解Leetcode 1865 Finding Pairs With a Certain Sum

基本上用 hashmap。解釋為什麼要使用排序和二元搜尋找來優化程式碼

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Basically use hashmap. Explain why  one should use sorting and binary search to optimize the code.

[codes on Leetcode]https://leetcode.com/problems/finding-pairs-with-a-certain-sum/solutions/6925404/unordered-map-sort-binary-search-c-37ms-99-37-py3-97-45/

[Leetcode playlist]https://www.youtube.com/watch?v=LJPL-Ukxf8w&list=PLYRlUBnWnd5IdDHk2BjqXwesydU17z_xk

Py3 C++位元計算bitset速解Leetcode難題3307 Find the K th Character in String Gam...

Py3 C++位元計算bitset速解Leetcode難題3307  Find the K th Character in String Game II

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Py3排序 C++nth_element速解Leetcode 2099 Find Subsequence of Length K With t...

Py3排序 C++nth_element速解Leetcode 2099  Find Subsequence of Length K With the Largest Sum

C++的nth_element很好用，基本上是做partition，在這個問題可取代sort

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C++'s nth_element is very useful. It basically does partitioning and can replace sort in this problem.

[codes on Leetcode]https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/solutions/6893606/nth-element-counting-sort-c-100-py3-1-line/

Py3 C++計數排序counting sort解Leetcode 2294 Partition Array Such That Maximu...

Py3 C++計數排序counting sort解Leetcode 2294  Partition Array Such That Maximum Difference Is K

基本上使用Greedy sort，而排序就用counting sort

[Python C++計數排序與一行解Leetcode 1051 Height Checker]https://www.youtube.com/watch?v=dybiq3pg-Os

[ Leetcode play list]https://www.youtube.com/playlist?list=PLYRlUBnWnd5IdDHk2BjqXwesydU17z_xk

2025資訊安全Steganography隱寫術Python實作

Py3 C++ DFS解Leetcode難題1298 Maximum Candies You Can Get from Boxes

Py3 C++ DFS解Leetcode難題1298  Maximum Candies You Can Get from Boxes

[codes on Leetcode]https://leetcode.com/problems/maximum-candies-you-can-get-from-boxes/solutions/6805859/dfs-bfs-for-a-tree-beats-100/

[Tree/graph list]https://www.youtube.com/watch?v=vdar3a_ZdCI&list=PLYRlUBnWnd5Kt0-3un43cwY6yT_il8NWe

C++Py3重複組合排容原理解Leetcode2929 Distribute Candies Among Children II

C++Py3重複組合排容原理解Leetcode2929  Distribute Candies Among Children II

Use combinatorial number with repetition & Inclusion-Exclusion Prinple to solve

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C++ DFS BFS解答Leecode難題3373 Maximize the Number of Target Nodes After Co...

C++ DFS BFS解答Leecode難題3373  Maximize the Number of Target Nodes After Connecting Trees II

圖論問題，跟bipartite有關

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Graphic question is related to the bipartite.

[codes on Leecode]https://leetcode.com/problems/maximize-the-number-of-target-nodes-after-connecting-trees-ii/solutions/6791084/dfs-bfs-with-parity-bitset-beats-100/

[Tree & Graph ]https://www.youtube.com/watch?v=vdar3a_ZdCI&list=PLYRlUBnWnd5Kt0-3un43cwY6yT_il8NWe

2025 AES 像素pixel加密圖檔解密

2025 C++ opencv卷積計算與影像處理

C++ Py3計數解Leetcode 2131 Longest Palindrome by Concatenating Two Letter ...

C++ Py3計數解Leetcode 2131  Longest Palindrome by Concatenating Two Letter Words

回文問題常被問到。這題基本上可以用計數的方法來解決。重點是兩個字母的字串 xy 和 yx 可以配對。

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Palindrome question is quite often asked. This question can be solved basically by using counting. It's important to know the 2-letter strings xy & yx can be paired.

[codes on Leetcode]https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/solutions/6778069/2d-array-counter-freq-count-c-c-py3-beats-100/

[C, C++ ,python速解迴文Leetcode 2108 Find First Palindromic String in the Array]https://www.youtube.com/watch?v=eXhdv8jDpao

C++ opencv selectROI擷圖與馬賽克

2025 AES opencv python圖檔加密

opencv C++使用卷積convolution/correlation進行影像處理

 

 opencv C++使用卷積convolution/correlation進行影像處理 

C/C++/Py3使用荷蘭旗演算3 pointer解Leetcode 75 Sort Colors

C C++ Py3使用荷蘭旗演算3 pointer解Leetcode 75 Sort Colors

一次走訪演算採用於荷蘭旗演算法。

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2025 opencv C++萬用VideoCapture Class

C++ Py3 Greedy 2 pointer速解(含1行解)Leetcode 2900 Longest Unequal Adjacent ...

C++ Py3 Greedy 2 pointer速解2900  Longest Unequal Adjacent Groups Subsequence I

C++ 會採用 2 -pointers主要的原因，就是不要額外的陣列，達到真正的O(1)空間解。

[Py3一行解請進]

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AES 256文字加密python實作

2025簡易opencv C++色階、負片處理

C++ Py3 Greedy速解Leetcode 2918 Minimum Equal Sum of Two Arrays After Rep...

C++ Py3 Greedy速解Leetcode 2918  Minimum Equal Sum of Two Arrays After Replacing Zeros

影片展示如何使用C++ STL編寫一個簡短的C++解答； Python程式碼也是按照類似的方式完成的。

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python模擬Diffie Hellman金鑰交換與淺談量子電腦Shor演算攻擊

python requests股市爬蟲與pyplot數據視覺化操作

Python code如下:

2025安裝C++ opencv與測試秀圖

2025 RSA演算 python實作加密解密

C++ OOP洗牌解Leetcode 384 Shuffle an Array

C++ oop洗牌解Leetcode 384  Shuffle an Array

[codes on Leetcode]https://leetcode.com/problems/shuffle-an-array/solutions/6676446/stl-shuffle-vs-fisher-yates-algorithm/

[C++洗牌shuffle與Fisher Yates演算, 大樂透開獎]

python單一迴圈解答最佳股票的買賣時機LeetCode 121 Best Time to Buy and Sell Stock

先說明一下這是後知後覺的解答，所謂後知就是股票價格已知存在陣列(清單)，當然就要用迴圈練習，雙迴圈暴力解需時O(n**2)，當然不用，採python單一迴圈解答「最佳股票的買賣時機#LeetCode 121  Best Time to Buy and Sell Stock」，解法簡單快速O(n)時間。

C++ Py3計數解Leetcode 781 Rabbits in Forest

C++ Py3計數解Leetcode 781 Rabbits in Forest

[codes on Leetcode]https://leetcode.com/problems/rabbits-in-forest/solutions/6668360/group-numbers-with-x-at-most-size-x-1-1-liner-beats-100/

[Python C++計數速解Leetcode 945 Minimum Increment to Make Array Unique]https://www.youtube.com/watch?v=tS-kunvQwcc

C++ class物件導向初探與實作

python版教科書級RSA產生key

有些版次的車輪沒造好，就自己造，以下為教科書版能處理1024-bit RSA的python程式

C++用mt19937虛擬亂數、不同機率分佈與求圓周率

C++用C rand虛擬亂數、陣列及萬用標頭檔使用

2025安裝wireshark並抓ICMP封包

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資安威脅與惡意軟體測驗檢討與wireshark解讀http封包中密碼

C++作業Leetcode 70 Climbing Stairs爬樓梯fibonacci費氏數列動態規劃實作

Fibonacci費式數列、Leetcode 70爬樓梯與動態規劃

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

[Py3 解含過程輸出請進]

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

[Py3解請進]

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

[解答請進]

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

[Py3解請進]

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)

[C++解請進]

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

[Py3 code請進]

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

[Py3解請進]

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。

[Python解請進]

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.

[Py3解答請進]

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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