Combine AoC Repos

2015/day04/input

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+yzbqklnj

2015/day04/main.go

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+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"log"
+	"strconv"
+)
+
+func main() {
+	var readInp string
+	for {
+		_, err := fmt.Scan(&readInp)
+		if err != nil {
+			if err != io.EOF {
+				log.Fatal(err)
+			}
+			break
+		}
+	}
+	firstCoin := searchChunk(readInp, 0, 1000000000)
+	fmt.Printf("\n%s%d :: %d\n", readInp, firstCoin, firstCoin)
+}
+
+func searchChunk(key string, start, end int) int {
+	// So we know it's still running
+	for i := start; i <= end; i++ {
+		coin := key + strconv.Itoa(i)
+		coinMd5 := fmt.Sprintf("%x", md5.Sum([]byte(coin)))
+		if isCoin(coinMd5, "000000") {
+			return i
+		}
+	}
+	return -1
+}
+
+func isCoin(s string, moneyMaker string) bool {
+	if len(s) < len(moneyMaker) {
+		return false
+	}
+	for i := 0; i < len(moneyMaker); i++ {
+		if s[i] != moneyMaker[i] {
+			return false
+		}
+	}
+	return true
+}

2015/day04/problem

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+                                           Advent of Code
+
+   br0xen 40*
+
+     • [About]
+     • [Stats]
+     • [Leaderboard]
+     • [Settings]
+     • [Log out]
+
+--- Day 4: The Ideal Stocking Stuffer ---
+
+   Santa needs help mining some AdventCoins (very similar to bitcoins) to use as gifts for all the
+   economically forward-thinking little girls and boys.
+
+   To do this, he needs to find MD5 hashes which, in hexadecimal, start with at least five zeroes.
+   The input to the MD5 hash is some secret key (your puzzle input, given below) followed by a
+   number in decimal. To mine AdventCoins, you must find Santa the lowest positive number (no
+   leading zeroes: 1, 2, 3, ...) that produces such a hash.
+
+   For example:
+
+     • If your secret key is abcdef, the answer is 609043, because the MD5 hash of abcdef609043
+       starts with five zeroes (000001dbbfa...), and it is the lowest such number to do so.
+     • If your secret key is pqrstuv, the lowest number it combines with to make an MD5 hash
+       starting with five zeroes is 1048970; that is, the MD5 hash of pqrstuv1048970 looks like
+       000006136ef....
+
+   Your puzzle answer was 282749.
+
+--- Part Two ---
+
+   Now find one that starts with six zeroes.
+
+   Your puzzle answer was 9962624.
+
+   Both parts of this puzzle are complete! They provide two gold stars: **
+
+   At this point, you should return to your advent calendar and try another puzzle.
+
+   Your puzzle input was yzbqklnj.
+
+   You can also [Shareon Twitter Google+ Reddit] this puzzle.
+
+References
+
+   Visible links
+   . http://adventofcode.com/
+   . http://adventofcode.com/about
+   . http://adventofcode.com/stats
+   . http://adventofcode.com/leaderboard
+   . http://adventofcode.com/settings
+   . http://adventofcode.com/auth/logout
+   . https://en.wikipedia.org/wiki/Bitcoin#Mining
+   . https://en.wikipedia.org/wiki/Bitcoin
+   . https://en.wikipedia.org/wiki/MD5
+   . https://en.wikipedia.org/wiki/Hexadecimal
+   . http://adventofcode.com/
+   . https://twitter.com/intent/tweet?text=I%27ve+completed+%22The+Ideal+Stocking+Stuffer%22+%2D+Day+4+%2D+Advent+of+Code&url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F4&related=ericwastl&hashtags=AdventOfCode
+   . https://plus.google.com/share?url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F4
+   . http://www.reddit.com/submit?url=http%3A%2F%2Fadventofcode%2Ecom%2Fday%2F4&title=I%27ve+completed+%22The+Ideal+Stocking+Stuffer%22+%2D+Day+4+%2D+Advent+of+Code