Reduce OSADamerau–Levenshtein space complexity from O(m*n) to O(3 * min(m,n))

[tang-hi]

When we calculate the distance of OSADamerau–Levenshtein, we actually calculate the matrix with dimension(m*n)
Suppose we have a matrix looks like

the value in (3,0) is always 3
the value in (3,1) depends on (3,0) (2,0) (2,1)
the value in (3,2) depends on (3,1) (2,1) (2,2) and (1,1)
we can found that the value in (row : i) only depends values in (row:i-1,i-2)
eg. the value in (row : 3) only depends values in (row:2,1)

So any row number >= 3, we could write it in (row %3, j),
eg.
write the value of (3,0) in (0,0) .... (3,j) in (0,j)
write the value of (4,0) in (1,0) .... (4,j) in (1,j)
write the value of (i,0) in (i%3,0) .... (i,j) in (i%3,j)

In this way, we only need the matrix with dimension(3, min(m,n)) to calculate OSADamerau–Levenshtein distance
Here is the code to illustrate my idea