753. Cracking the Safe.go

package leetcode

import"math"

constnumber="0123456789"

funccrackSafe(nint, kint) string {
ifn==1 {
returnnumber[:k]
 }
visit, total:=map[string]bool{}, int(math.Pow(float64(k), float64(n)))
str:=make([]byte, 0, total+n-1)
fori:=1; i!=n; i++ {
str=append(str, '0')
 }
dfsCrackSafe(total, n, k, &str, &visit)
returnstring(str)
}

funcdfsCrackSafe(depth, n, kint, str*[]byte, visit*map[string]bool) bool {
ifdepth==0 {
returntrue
 }
fori:=0; i!=k; i++ {
*str=append(*str, byte('0'+i))
cur:=string((*str)[len(*str)-n:])
if_, ok:= (*visit)[cur]; ok!=true {
 (*visit)[cur] =true
ifdfsCrackSafe(depth-1, n, k, str, visit) {
// 只有这里不需要删除
returntrue
 }
delete(*visit, cur)
 }
// 删除
*str= (*str)[0 : len(*str)-1]
 }
returnfalse
}