The 4 programming assignments build 1 project to build an IR system:
Indexer 1: Inverted Index (week 2).
Indexer 2: Index Compression (week 4).
Search Engine (week 5).
Web Crawler (week 7).
Manning, C.D., Raghaven, P., & Schütze, H. (2009). An Introduction to Information Retrieval (Online ed.). Cambridge, MA: Cambridge University Press. Available at https://web.stanford.edu/class/cs276