Added unorganized.md

gazeldx · gazeldx · commit d76779063cf8 · 2024-12-17T21:36:07.000+08:00
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+# LeetCode skills
+## Binary tree unified stack iteration
+`boolean mark` solution.
+
+## Dynamic programming
+- [647. Palindromic Substrings](https://leetcode.cn/problems/palindromic-substrings/)
+- [516. Longest Palindromic Subsequence](https://leetcode.cn/problems/longest-palindromic-subsequence/)
+For solving the above two issues, we can use two-dimensional array. Remember the `magic word`: **回文串，用一半，内环反**.
+
+The principle of `dynamic programming` is **from top to bottom, from left to right, from less to more, from near to far, from known to unknown**
+and **take turns being the boss**.
+
+## Monotonic stack
+* Push indies one by one.
+* Only the useful indies are kept in the stack. Useless indices are popped (or eaten by followed larger (or smaller) index).
+* 
