Add problem tagging guide

docs/tlx/slug-soal.md → docs/tlx/01-slug-soal.md

@@ -1,6 +1,5 @@
 # Panduan Membuat Slug Soal
 
-
 Setiap soal pada TLX memiliki sebuah *identifier* (pengenal) berupa sebuah string yang disebut *slug*, yang harus berbeda-beda. Biasanya, slug dibentuk dari judul soal, misalnya `tebak-angka`.
 
 Saat ini terdapat banyak kontes pada TLX. Mungkin saja ada dua soal dari dua kontes berbeda yang memiliki judul yang sama. Sebagai contoh, `Tebak Angka` adalah judul soal yang lumayan umum. Menggunakan `tebak-angka` sebagai slug tentu bukanlah ide yang baik.

docs/tlx/02-problem-tagging.md

@@ -0,0 +1,56 @@
+# Problem Tagging
+
+## A. Goals
+
+1. By viewing the list of tags, one can **discover new concepts** that they didn't know before.
+1. By clicking on one tag, one can practice with **relevant problems** that use the concepts.
+1. By solving problems tagged with a tag, one will **gain more experience** with the concepts.
+
+## B. Principles
+
+1. It is important to be **consistent** in choosing tags.
+   - Before tagging, please explore existing problem tagging in TLX, to see and "feel" the existing convention.
+
+## C. Choosing Tags
+
+1. Consider all intended solutions. For each solution, pick one or more appropriate tags, based on the following rules:
+   1. `constructive`
+      - Pick this tag if the solution is to **creatively** construct **any solution** which satisfies the provided criteria, out of (usually) **many possible solutions**.
+      - Don't pick this tag if the solution heavily relies on a well-known algorithm/technique. The emphasis here is "creatively".
+      - Usually, **interactive** problems will have this tag, because usually it requires creative solutions.
+   1. `data structure`
+      - `compression`
+        - Pick this tag if the solution requires "compressing" coordinates / array positions.
+      - `fenwick tree`
+        - Pick this tag if the solution can use either Fenwick tree or segment tree, e.g. just for **standard range query** capability.
+        - If we pick this tag, don't pick the `segment tree` tag.
+      - `segment tree`
+        - Pick this tag if the solution needs segment tree with **lazy propagation**.
+      - `prefix sum`
+        - Pick this tag if prefix sum is the **main idea** of the solution.
+        - Don't pick this tag if prefix sum is just for **optimizing** larger DP transition.
+   1. `dynamic programming`
+      - `combinatorics`
+        - Pick this tag if the DP is about counting number of ways.
+        - Pick this tag if the DP needs counting the number of ways to solve the problem. Example: printing K-th lexicographically smallest sequence.
+      - `tree`
+        - If we pick this tag, don't pick the `tree` tag.
+   1. `heuristic`
+      - Pick this tag if the scoring can be **partial** based on the creativity of the solution.
+      - Usually, output-only problems will have this tag.
+   1. `implementation`
+      - Pick this tag if the solution is to (almost) exactly do what the problem statement **literally says**.
+      - Don't pick this tag if there is one or more additional steps/insights needed. This tag is intended for beginners to practice implementing code. 
+   1. `math`
+      - `combinatorics`
+        - Pick this tag if the problem is about counting number of ways.
+        - If `dp:combinatorics` is already picked, don't pick this tag.
+      - `number theory`
+        - Pick this tag is the problem requires knowledge of properties of integers.
+2. For each of these tags, if it is picked, at least a subtag must be picked. If there are no appropriate subtag, **DON'T** pick the tag at all (or contact **fushar** to add a new subtag):
+   1. `data structure`
+   1. `searching`
+   1. `optimization trick`
+3. Also pick the `ad hoc` tag if the set of the tags (possibly empty) is a subset of the following:
+   1. `bitwise operation`
+   1. `constructive`