61 lines
959 B
Go
61 lines
959 B
Go
package main
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import (
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"bytes"
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"fmt"
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"os"
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)
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func main() {
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beg, end := []byte("165432"), []byte("707912")
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if len(os.Args) == 3 {
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beg, end = []byte(os.Args[1]), []byte(os.Args[2])
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}
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var count int
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for {
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if validate(beg) {
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count++
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}
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if bytes.Equal(beg, end) {
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break
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}
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beg = inc(beg)
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}
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fmt.Println(count)
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}
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func inc(num []byte) []byte {
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if len(num) == 0 {
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return []byte{'1'}
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} else if num[len(num)-1] == '9' {
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return append(inc(num[:len(num)-1]), '0')
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} else {
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num[len(num)-1]++
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}
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return num
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}
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func validate(num []byte) bool {
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var dup bool
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for k := range num {
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if countSeq(num, k) == 2 {
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dup = true
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}
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if len(num) > k+1 && num[k] > num[k+1] {
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return false
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}
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}
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return dup
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}
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func countSeq(num []byte, idx int) int {
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ret := 1
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if len(num) > idx+1 && num[idx+1] == num[idx] {
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ret += countSeq(num[idx+1:], 0)
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}
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if idx >= 1 && num[idx-1] == num[idx] {
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ret += countSeq(num[:idx], idx-1)
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}
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return ret
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}
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