func (x *suffixSortable) updateGroups(offset int) {
- prev := len(x.sa) - 1
- group := x.inv[x.sa[prev]+x.h]
- for i := prev; i >= 0; i-- {
- if g := x.inv[x.sa[i]+x.h]; g < group {
- if prev == i+1 { // previous group had size 1 and is thus sorted
- x.sa[i+1] = -1
- }
+ bounds := make([]int, 0, 4)
+ group := x.inv[x.sa[0]+x.h]
+ for i := 1; i < len(x.sa); i++ {
+ if g := x.inv[x.sa[i]+x.h]; g > group {
+ bounds = append(bounds, i)
group = g
- prev = i
}
- x.inv[x.sa[i]] = prev + offset
- if prev == 0 { // first group has size 1 and is thus sorted
- x.sa[0] = -1
+ }
+ bounds = append(bounds, len(x.sa))
+
+ // update the group numberings after all new groups are determined
+ prev := 0
+ for _, b := range bounds {
+ for i := prev; i < b; i++ {
+ x.inv[x.sa[i]] = offset + b - 1
+ }
+ if b-prev == 1 {
+ x.sa[prev] = -1
}
+ prev = b
}
}