C C++ GCD LCM解Leetcode難題2197 Replace Non Coprime Numbers in Array[含Py3 code]

C C++ GCD LCM解Leetcode難題2197  Replace Non Coprime Numbers in Array

用binary Euclidean algorithm定義gcd，然後定義lcm之後就是用stack

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C++示範bitset取代hashset解Leetcode 1733 Minimum Number of People to Teach(含Py3 code)

C++示範bitset取代hashset解Leetcode 1733  Minimum Number of People to Teach

C++ STL的unordered_set與bitset都能解這題，但執行效率差很多，有誰寫C++其執行效能要比類似的Python code還要慢上好久倍?用hashset就如此

[Python code請進 ]

Py3 C++算術建構解1317 Convert Integer to the Sum of Two No Zero Integers

Py3  C++算術建構解1317  Convert Integer to the Sum of Two No Zero Integers

[Py3解請進]

C++C py3 log4 prefix sum, bits解Leetcode難題3495 Minimum Operations to Mak...

C++C py3 log4 prefix sum/bits解Leetcode難題3495  Minimum Operations to Make Array Elements Zero

ceil(log4(x)) 可以透過 clz 計算；將 expSum 定義為部分和來計算。

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C++ C Py3 Rust數bits解Leetcode 2749 Minimum Operations to Make the Intege...

C++ C Py3 Rust數bits解Leetcode 2749  Minimum Operations to Make the Integer Zero

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Py3 C++排序loop解Leetcode 3025 3027 Find the Number of Ways to Place People

Py3 C++排序loop解Leetcode 3025 3027 Find the Number of Ways to Place People

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C++回遡與bitmask解Leetcode 37數獨Sudoku

C++回遡與bitmask解Leetcode 37數獨Sudoku

有些經典問題值得一解再解，雖然不是最佳解，也要比Leetcode Editorial的解有效許多。解數獨，回遡乃基本款，但加上bitmask就能篩掉許多無用的測試，就更快許多

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Some classic problems are worth solving again and again. Although they are not the best solutions, they are much more effective than Leetcode Editorial's solutions. Solve Sudoku by using backtracking is the basic version, but add bitmask to filter out many useless tests can make it much faster.

[codes on Leetcode]https://leetcode.com/problems/sudoku-solver/solutions/7139967/new-sol-bitmask-backtracking-beats-100/

[其他採回溯未用bitmask解法]https://www.youtube.com/watch?v=wviWrbbOdYE

Py3 C++速解Leetcode 3446 Sort Matrix by Diagonals/with Py3 code

Py3 C++速解Leetcode 3446  Sort Matrix by Diagonals

矩陣問題都是很好的迴圈、陣列練習，又加上排序那就是很好的練習題

[Py3 code請進]

C++ dp動態規劃解Leetcode 3459 Length of Longest V Shaped Diagonal Segment

C++ dp動態規劃解Leetcode 3459  Length of Longest V Shaped Diagonal Segment

採DP動態規劃迭代版本解難題，需要定義V-shaped distance

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Using the DP dynamic programming iterative version, it is necessary to define the V-shaped distance

[codes on Leetcode]https://leetcode.com/problems/length-of-longest-v-shaped-diagonal-segment/solutions/7126168/dp-recursive-dfs-or-iteration-beats-100/

[DP動態規劃Playlist]https://www.youtube.com/watch?v=30yq3fmE6E8&list=PLYRlUBnWnd5K_XYUesV9oc6M9ONXII61T

Py3 C++畢氏定理速解Leetcode 3000 Maximum Area of Longest Diagonal Rectangle

Py3 C++畢氏定理速解Leetcode 3000  Maximum Area of Longest Diagonal Rectangle

Py3 C++ Pythagorean Theorem Quick Solution Leetcode 3000 Maximum Area of​​ Longest Diagonal Rectangle

[codes on Leetcode]https://leetcode.com/problems/maximum-area-of-longest-diagonal-rectangle/solutions/7122597/easy-1-pass-vs-max-with-custom-cmp-c-py3-beats-100/

[Leetcode playlist]https://www.youtube.com/watch?v=VfRVKO7El9w&list=PLYRlUBnWnd5IdDHk2BjqXwesydU17z_xk

Py3 C++ sliding window速解Leetcode1493 Longest Subarray of 1's After Dele...

Py3 C++ sliding window速解Leetcode1493  Longest Subarray of 1's After Deleting One Element

示範如何從一般  sliding window解答簡化成單迴圈解答解無if

[Py3解在此，請進]

C++ dp動態規劃速解Leetcode 1277 Count Square Submatrices with All Ones

C++ dp動態規劃速解Leetcode 1277  Count Square Submatrices with All Ones

使用matrix當成state matrix

[codes on Leecode]https://leetcode.com/problems/count-square-submatrices-with-all-ones/solutions/7101478/reuse-matrix-as-state-matrix-beats-100/

[DP play list]https://www.youtube.com/watch?v=30yq3fmE6E8&list=PLYRlUBnWnd5K_XYUesV9oc6M9ONXII61T

Py3 C++陣列迴圈速解Leetcode 1323 Maximum 69 Number

Py3 C++陣列迴圈速解Leetcode 1323  Maximum 69 Number

學程式的第一式，就是要會活用陣列迴圈，足以解Leetcode 1323. Maximum 69 Number 

[Py3解請進]

Leetcode 342 Power of Four幾個C++一行解

Leetcode 342  Power of Four幾個C++一行解

[codes on Leetcode]https://leetcode.com/problems/power-of-four/solutions/7081839/9-ways-of-bit-manipulation-1-liner-beats-100/

[bit/ bitmask playlist]https://www.youtube.com/watch?v=Hw1fnQA8Nk8&list=PLYRlUBnWnd5K8FlzJ6tOswqQcsk7R1Duh

C++一行解Leetcode 326 Power of Three

C++一行解Leetcode 326  Power of Three

利用3的羃次方的因數也是3的羃次方，導出一行C++程式碼

[解答請進]

C++ DP速解難題leetcode 3363 Find the Maximum Number of Fruits Collected/Py3 code inclusive

C++ DP速解難題leetcode 3363  Find the Maximum Number of Fruits Collected

[Python解請進]

segment tree C++解Leetcode 3479 Fruits Into Baskets III

segment tree C++解Leetcode 3479  Fruits Into Baskets III

線段樹(segment tree)是一種進階的資料結構，可以用來解決一些 LeetCode 難題。

線段樹本質上是一棵二元樹；它可以用二元樹來實現，但更常見的是使用陣列表示。這題需要用到有最大值的線段樹；以及一種尋找第一個不小於target的basket然後更新的方法。

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Segment tree is an advance data struture which can solve several Leetcode questions.

Segment tree is basically a binary tree, ; it can be implemented by using binary tree, but most frequently its array representation way. This question needs the segment tree with max; and a method which  searchs the 1st basket not less than target & then updates it.

[Solution to  3477  Fruits Into Baskets II]https://leetcode.com/problems/fruits-into-baskets-ii/solutions/7045085/easy-subtraction-beats-100/

二元搜尋sliding window C++ py3解Leetcode 2106難題Maximum Fruits Harvested After ...

二元搜尋sliding window cpp py3解Leetcode 2106難題Maximum Fruits Harvested After at Most K Steps

[C++ solution請進]

Py3 C++奇偶交錯奇偶子數列解Leecode 3201 Find the Maximum Length of Valid Subsequ...

Py3  C++奇偶交錯奇偶子數列解Leecode 3201  Find the Maximum Length of Valid Subsequence I

求最長有效子序列，使得 (sub[0] + sub[1]) % 2 == (sub[1] + sub[2]) % 2 == ... == (sub[x - 2] + sub[x - 1]) % 2，有 3 種可能的情況

-全為偶數

-全為奇數

-或奇偶交錯子序列

[Py3解請進]

Py3 C++母音 vowel mask速解Leetcode 3136 Valid Word

Py3 C++母音 vowel mask速解Leetcode 3136  Valid Word

Leetcode有許多判斷母音的問題，採用bitmask方式，迅速又方便

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Leetcode has many problems in determining vowels. Using the bitmask method is fast and convenient.

[codes onLeetcode]https://leetcode.com/problems/valid-word/solutions/6959558/bitmask-for-vowel-bitset-beats-100/