int editDistance(T)(T[] s1, T[] s2) {
    if (len(s1) > len(s2)) { auto sa = s1; s1 = s2; s2 = sa; }
    auto r1 = range(len(s2) + 1);
    auto r2 = new int[len(r1)];
    foreach (i, c1; s1) {
        r2[0] = i + 1;
        foreach (j, c2; s2)
            r2[j+1] = c1 == c2 ? r1[j] : min(r2[j], r1[j], r1[j+1]) + 1;
        auto ra = r1; r1 = r2; r2 = ra;
    }
    return r1[$ - 1];
}

def editDistanceFast(s1, s2, r1=[0]*35, r2=[0]*35):
    if s1 == s2: return 0
    if len(s1) > len(s2):
        s1, s2 = s2, s1
    len_s2 = len(s2)
    assert len(s2) <= 34, "Error: one input sequence"\
           "is too much long (> 34), use editDistance()."
    for i in xrange(len_s2 + 1):
        r1[i] = i
        r2[i] = 0
    i = 0
    for c1 in s1:
        r2[0] = i + 1
        j = 0
        for c2 in s2:
            if c1 == c2:
                r2[j+1] = r1[j]
            else:
                a1 = r2[j]
                a2 = r1[j]
                a3 = r1[j+1]
                if a1 > a2:
                    if a2 > a3:
                        r2[j+1] = 1 + a3
                    else:
                        r2[j+1] = 1 + a2
                else:
                    if a1 > a3:
                        r2[j+1] = 1 + a3
                    else:
                        r2[j+1] = 1 + a1
            j += 1
        aux = r1; r1 = r2; r2 = aux
        i += 1
    return r1[len_s2]

Store:     Size:     Access cost (clocks):
Registers  64B       1
L1 cache   32KB      3
L2 cache   4MB       14
DRAM       4GB       200
Disk       500GB     15M

>>> 5.89 + 3.99
9.879999999999999
>>> from decimal import Decimal as D
>>> print D("5.89") + D("3.99")
9.88