mirror of
https://github.com/cubixle/codekata-golang.git
synced 2026-04-24 19:54:43 +01:00
55 lines
770 B
Go
55 lines
770 B
Go
package main
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import (
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"fmt"
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"math"
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"math/big"
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"time"
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)
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func main() {
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solution()
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}
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func solution() {
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ts := time.Now()
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n := math.Sqrt(19293949596979899)
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t := math.Sqrt(10203040506070809)
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for i := n; i >= t; i-- {
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x := (&big.Int{}).SetInt64(int64(i))
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if !isEndsWith37(x.String()) {
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continue
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}
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if isMatch(x.Mul(x, x)) {
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fmt.Println(x)
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fmt.Println("num is", int64(i)*10)
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fmt.Println(time.Since(ts))
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break
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}
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}
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}
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func isEndsWith37(s string) bool {
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if len(s) == 0 {
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return false
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}
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c := s[len(s)-1]
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if c == '3' || c == '7' {
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return true
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}
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return false
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}
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func isMatch(i *big.Int) bool {
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x := i.String()
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num := x[0]
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for i := 2; i < len(x); i += 2 {
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if x[i] == num+1 {
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num++
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continue
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}
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return false
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}
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return true
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}
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