Perhaps you should try some spelling variations:
"coder coder ray clustering problem" » "coder coder ray covering problem" (Expand search), "coder coder grey clustering problem" (Expand search), "coder coder by clustering problem" (Expand search), "coder coder graph clustering problem" (Expand search), "coder decoder ray clustering problem" (Expand search), "code code ray clustering problem" (Expand search), "decoder codec ray clustering problem" (Expand search), "coder code rac clustering problem" (Expand search), "coder order ray clustering problem" (Expand search)
"api pitons python python programming" » "api pitons pythons python programming" (Expand search), "api pitons piton python programming" (Expand search), "api pitons pytm python programming" (Expand search), "api citons python python programming" (Expand search), "api pitoni python python programming" (Expand search), "api pitoes python python programming" (Expand search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("coder coder ray clustering problem") OR ("api pitons python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder coder ray clustering problem\") OR (\"api pitons python python programming\"))".
• Removing quotes may allow a broader search: (( coder coder ray clustering problem ) OR ( api pitons python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder coder ray clustering problem") OR ("api pitons python python programming"))*.