Given the dimensions of n matrices M1..Mn, what is the minimum number of multiplication in M1 x M2 x ... x Mn.
Suppose dimensions are given as [10, 30, 5, 60], meaning 3 matrices with dimensions 10 x 30, 30 x 5 and 5 x 60, (AB)C requires 10x30x5 + 10x5x60 = 4500 operations while A(BC) requires 30x5x60 + 20x30x60 = 27000 operations. Therefore, the function should return 4500.