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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C++Python Greedy DP速解Leetcode 1014 Best Sightseeing Pair

C++Python Greedy DP速解Leetcode 1014  Best Sightseeing Pair算是貪婪演算還是動態規劃，其實都算解法類似Kadane演算法。

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Leetcode 1014. Best Sightseeing Pair is considered greedy algorithm or dynamic programming, but it is actually both. It's similar to Kadane's Algorithm

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python Keras使用仿AlexNet針對oxflower達到100趴的辨識率實測

C++BFS走訪 level排序與DFS cycle長度計數解Leetcode 2471 Minimum Number of Operatio...

C++BFS走訪 level排序與DFS cycle長度計數解Leetcode 2471  Minimum Number of Operations to Sort a Binary Tree by Level

解圖論問題Leetcode 2471. Minimum Number of Operations to Sort a Binary Tree by Level，這不算稀奇，但當中還用到置換群(permutation group)的概念就比較特別。

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Solve the graph theory problem Leetcode 2471. Minimum Number of Operations to Sort a Binary Tree by Level. This is not unusual, but the concept of permutation group is also used in it, which is quite special.

[codes on Leetcode]https://leetcode.com/problems/minimum-number-of-operations-to-sort-a-binary-tree-by-level/solutions/6175677/bsf-levelwise-transversal-compare-with-s-l164/

[Tree Graph Playlist]https://www.youtube.com/watch?v=bna7aw7dkPY&list=PLYRlUBnWnd5Kt0-3un43cwY6yT_il8NWe