Fixed two equations at the end

Update fenwick.md

I think this capture the original intent.
You never know when it comes to notation on probabili...

fixed another typo

Minor grammar fixes in segment tree introduction

Update 2SAT.md Practice Problems

Reordered the practice problems to put "Codeforces: The Door Problem" (easier) before "UVA: Rect...

Simplify code for calculating phi for 1..n

The loop already sets `phi[i] = i` so no need to set phi[0] and phi[1] manually.

Update manacher.md

Lengths "i - 2" and "i - 4" was written instead of "l - 2" and "l - 4" in Line 16.

Relinking to Codeforces Gym per codebreaker request

re-linking to Codeforces gym and DMOJ per Codebreaker request

Remove redundant inline math nesting

Change to MkDocs site generator with Material for MkDocs theme

Even-length case is now reduced to the odd-length.

articles + typos fix

clarification

simpler explanation and proof for the algorithm, additional explanation for time complexity

Another problem example from Codechef

add another method of czt

Fix collinear line case in Monotone Chain

Updated fft.md by fixing TeX

Modified the 4 TeX equations under header "Improved implementation: in-place computation"