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// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
package utils
import (
"fmt"
"math"
)
var _ = fmt.Print
func slice_iter(strs []string) func() (string, bool) {
i := 0
limit := len(strs)
return func() (string, bool) {
if i < limit {
i++
return strs[i-1], false
}
return "", true
}
}
// Prefix returns the longest common prefix of the provided strings
func Prefix(strs []string) string {
return LongestCommon(slice_iter(strs), true)
}
// Suffix returns the longest common suffix of the provided strings
func Suffix(strs []string) string {
return LongestCommon(slice_iter(strs), false)
}
func min(a ...int) int {
ans := math.MaxInt
for _, x := range a {
if x < ans {
ans = x
}
}
return ans
}
func LongestCommon(next func() (string, bool), prefix bool) string {
xfix, done := next()
if xfix == "" || done {
return ""
}
for {
q, done := next()
if done {
break
}
q_len := len(q)
xfix_len := len(xfix)
max_len := min(q_len, xfix_len)
if max_len == 0 {
return ""
}
if prefix {
for i := 0; i < max_len; i++ {
if xfix[i] != q[i] {
xfix = xfix[:i]
break
}
}
} else {
for i := 0; i < max_len; i++ {
xi := xfix_len - i - 1
si := q_len - i - 1
if xfix[xi] != q[si] {
xfix = xfix[xi+1:]
break
}
}
}
}
return xfix
}
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