根据第2列中的最大值找到第1列中值的最高组合-R

Question

I have a dataframe with 3 columns(in reality of ~2000 rows). I want to return the values of column A which has the highest maximum total score in column B, with the restriction of a max value in column C. For example:

colName    col1  col2
John     7      50
Jim      3      25
James    2      25
Peter    9      110
Robert   1      75
Hank     1      75

Let's say the max total/sum value of col2 is 100. The highest combination of combined values in col1 would be 7+3+2=12. I would like to return the list of names that would be returned: John, Jim, James

Q1: How would I do this?

Q2: Alternatively, It would be interesting to return the entire rows of the dataframe with the values of the highest possible combination in a dataframe:

 colName    col1  col2
    John     7      50
    Jim      3      25
    James    2      25

Answer 1

What you're referring to is a 0/1 knapsack problem . The adagio package implements a knapsack solver in R.

> tbl
# A tibble: 6 x 3
  colName  col1  col2
  <chr>   <int> <int>
1 John        7    50
2 Jim         3    25
3 James       2    25
4 Peter       9   110
5 Robert      1    75
6 Hank        1    75
> tbl <- tbl[tbl$col2 <= 100, ]  # `adagio` will complain otherwise
> soln <- knapsack(tbl$col2, tbl$col1, 100)
> tbl[soln$indices, ]
# A tibble: 3 x 3
  colName  col1  col2
  <chr>   <int> <int>
1 John        7    50
2 Jim         3    25
3 James       2    25