grep+ found these files to match your search:
p10819.cpp: //medium, knapsack, dp, coins p10130.cpp: //medium, knapsack, dp, coins p431.cpp: //medium, dp, knapsack p10373.cpp: //medium, knapsack, dp, coins
grep+ searches the database of Valladolid problems that I solved (or tried to). You can give it keywords like "dp", "graphs", "math", "brute force", etc. and it will give you a list of problem numbers that (in my opinion) match the keywords. The database contains 1408 problems.
Please ignore anything that appears after "UNSOLVED:". As you probably know, not being able to solve a problem after many attempts can be very frustrating.