Perhaps you should try some spelling variations:
"coder code _ combinatorial problem" » "coder code _ combinatorial problems" (Expand search), "code code _ combinatorial problem" (Expand search), "modern code _ combinatorial problem" (Expand search), "color code _ combinatorial problem" (Expand search)
"api python python python programming" » "api pythons python python programming" (Expand search), "api piton python python programming" (Expand search), "api pitons python python programming" (Expand search), "rpa python python python programming" (Expand search)

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder code _ combinatorial problem\") OR (\"api python python python programming\"))~".
• Removing quotes may allow a broader search: (( coder code _ combinatorial problem ) OR ( api python python python programming ))~.
• Adding a wildcard symbol may retrieve word variants: (("coder code _ combinatorial problem") OR ("api python python python programming"))*.