55 lines
962 B
Go
55 lines
962 B
Go
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package main
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import (
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"bufio"
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"fmt"
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"os"
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"strconv"
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"time"
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)
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func main() {
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start := time.Now()
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partOne()
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duration := time.Since(start)
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fmt.Printf("p1: %s, p2: n/a\n", duration)
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}
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func partOne() {
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f, _ := os.Open("input")
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reader := bufio.NewReader(f)
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scanner := bufio.NewScanner(reader)
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scanner.Scan()
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doorPubKey, _ := strconv.Atoi(scanner.Text())
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scanner.Scan()
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cardPubKey, _ := strconv.Atoi(scanner.Text())
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subjectNumber := 7
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value := 1
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magicPrime := 20201227
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loopCount := 1
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doorLoopCount := 0
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cardLoopCount := 0
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for {
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value = (value * subjectNumber) % magicPrime
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if value == doorPubKey {
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doorLoopCount = loopCount
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}
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if value == cardPubKey {
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cardLoopCount = loopCount
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}
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loopCount = loopCount + 1
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if doorLoopCount != 0 && cardLoopCount != 0 {
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break
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}
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}
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value = 1
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subjectNumber = cardPubKey
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for i := 0; i < doorLoopCount; i = i + 1 {
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value = (value * subjectNumber) % magicPrime
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}
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fmt.Println(value)
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}
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