Problem 1889. Get ranking of a combination looking for speed.
I have the numbers pulled without replacement from the set [1 2 3 4 5 6 7 8 9 10 11 12 13]; They are then ordered from least to greatest.
So a selection of [3 2 9], [9 2 3] are both considered to be [2 3 9].
There are 286 unique selections possible. These can be ordered in lexicographic order:
Element 1 = [ 1 2 3] Element 2 = [ 1 2 4] Element 3 = [ 1 2 5] Element 4 = [ 1 2 6] Element 5 = [ 1 2 7] Element 6 = [ 1 2 8] Element 7 = [ 1 2 9] Element 8 = [ 1 2 10] Element 9 = [ 1 2 11] Element 10 = [ 1 2 12] Element 11 = [ 1 2 13] Element 12 = [ 1 3 4] Element 13 = [ 1 3 5] Element 14 = [ 1 3 6] Element 15 = [ 1 3 7] ... Element 285 = [10 12 13] Element 286 = [11 12 13]
Given the three ordered values as a row vector, return the element number.
The test suite only passes if it is faster that my reference code.
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