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
