feat: add new lc problems

[yanglbme]

No description provided.

[idoocs]

Images automagically compressed by Calibre's image-actions ✨

Compression reduced images by 35.8%, saving 99.63 KB.

Filename	Before	After	Improvement	Visual comparison
solution/3500-3599/3528.Unit Conversion I/images/1745660099-FZhVTM-example1.png	39.18 KB	35.18 KB	-10.2%	View diff
solution/3500-3599/3529.Count Cells in Overlapping Horizontal and Vertical Substrings/images/1745660164-PjoTAy-gridtwosubstringsdrawio.png	19.45 KB	6.09 KB	-68.7%	View diff
solution/3500-3599/3529.Count Cells in Overlapping Horizontal and Vertical Substrings/images/1745660201-bMoajW-gridexample2fixeddrawio.png	14.36 KB	4.17 KB	-70.9%	View diff
solution/3500-3599/3530.Maximum Profit from Valid Topological Order in DAG/images/1745660258-BXXGjv-screenshot-2025-03-11-at-021131.png	12.68 KB	4.70 KB	-63.0%	View diff
solution/3500-3599/3530.Maximum Profit from Valid Topological Order in DAG/images/1745660268-mJrEKY-screenshot-2025-03-11-at-023558.png	18.56 KB	9.04 KB	-51.3%	View diff
solution/3500-3599/3531.Count Covered Buildings/images/1745660407-qtNUjI-telegram-cloud-photo-size-5-6212982906394101085-m.jpg	7.67 KB	6.39 KB	-16.7%	View diff
solution/3500-3599/3531.Count Covered Buildings/images/1745660407-tUMUKl-telegram-cloud-photo-size-5-6212982906394101086-m.jpg	7.26 KB	6.05 KB	-16.6%	View diff
solution/3500-3599/3532.Path Existence Queries in a Graph I/images/1745660506-eNVQtC-screenshot-2025-03-26-at-122249.png	38.58 KB	20.04 KB	-48.0%	View diff
solution/3500-3599/3534.Path Existence Queries in a Graph II/images/1745660620-PauXMH-4149example1drawio.png	13.39 KB	2.93 KB	-78.1%	View diff
solution/3500-3599/3534.Path Existence Queries in a Graph II/images/1745660627-mSVsDs-4149example2drawio.png	9.64 KB	2.02 KB	-79.1%	View diff
solution/3500-3599/3535.Unit Conversion II/images/example1.png	36.46 KB	31.15 KB	-14.6%	View diff
solution/3500-3599/3535.Unit Conversion II/images/example2.png	60.74 KB	50.58 KB	-16.7%	View diff

2053 images did not require optimisation.