updating chapter 4 and rebuilding book.pdf

[eng-abdelrahman-sharaf]

Fix efficiency comparison in Chapter 04 (Algorithm 2 is fastest)

Measured execution time of all algorithms using C++ code (n values from the table). Corrected the previous assumption: Algorithm 2 is demonstrably the fastest, not Algorithm 3. Updated Chapter 04 in book.pdf to reflect this finding.

The code : https://github.com/eng-abdelrahman-sharaf/shared_repo/blob/main/cphb-page-45.cpp

The Output : https://github.com/eng-abdelrahman-sharaf/shared_repo/blob/main/output_cphb_page_45.txt