Advent Of Code

day1.go

package main

import (
	"fmt"
	"strconv"
	"math"
)

func main() {
	input := "823936645345581272695677318513459491834641129844393742672553544439126314399846773234845535593355348931499496184839582118817689171948635864427852215325421433717458975771369522138766248225963242168658975326354785415252974294317138511141826226866364555761117178764543435899886711426319675443679829181257496966219435831621565519667989898725836639626681645821714861443141893427672384716732765884844772433374798185955741311116365899659833634237938878181367317218635539667357364295754744829595842962773524584225427969467467611641591834876769829719248136613147351298534885563144114336211961674392912181735773851634298227454157885241769156811787611897349965331474217223461176896643242975397227859696554492996937235423272549348349528559432214521551656971136859972232854126262349381254424597348874447736545722261957871275935756764184378994167427983811716675476257858556464755677478725146588747147857375293675711575747132471727933773512571368467386151966568598964631331428869762151853634362356935751298121849281442128796517663482391226174256395515166361514442624944181255952124524815268864131969151433888721213595267927325759562132732586252438456569556992685896517565257787464673718221817783929691626876446423134331749327322367571432532857235214364221471769481667118117729326429556357572421333798517168997863151927281418238491791975399357393494751913155219862399959646993428921878798119215675548847845477994836744929918954159722827194721564121532315459611433157384994543332773796862165243183378464731546787498174844781781139571984272235872866886275879944921329959736315296733981313643956576956851762149275521949177991988236529475373595217665112434727744235789852852765675189342753695377219374791548554786671473733124951946779531847479755363363288448281622183736545494372344785112312749694167483996738384351293899149136857728545977442763489799693492319549773328626918874718387697878235744154491677922317518952687439655962477734559232755624943644966227973617788182213621899579391324399386146423427262874437992579573858589183571854577861459758534348533553925167947139351819511798829977371215856637215221838924612644785498936263849489519896548811254628976642391428413984281758771868781714266261781359762798"
	
	inputNum := toInt(input)
		
	// first challenge
	matches  := matchAdjacent(inputNum)
	fmt.Println(sum(matches))
	
	// second challenge
	matches = matchHalfway(inputNum)
	fmt.Println(sum(matches))
	
	// Generalize
	fmt.Println(sum(matchStep(inputNum, 1)) == sum(matchAdjacent(inputNum)))
	fmt.Println(sum(matchStep(inputNum, len(inputNum)/2)) == sum(matchHalfway(inputNum)))
	
	
}


func matchAdjacent(ints []int) []int {
	var matched []int
	prev := ints[len(ints)-1]
	for _, v := range ints {
	   if v == prev {
	     matched = append(matched, v)
	   }
	   prev = v
	}
	return matched
}

func matchHalfway(ints []int) []int {
	l := len(ints)
  	steps := l/2
	var matched []int
	
	for i, v := range ints {
	   idx := i+steps
	   if idx > l-1 {
	      idx = int(math.Mod(float64(idx), float64(l)))
	   }
	   if v == ints[idx] {
	     matched = append(matched, v)
	   }
	}
	return matched
}


func matchStep(ints []int, steps int) []int {

	l := len(ints)
	var matched []int
	
	for i, v := range ints {
	   idx := i+steps
	   if idx > l-1 {
	      idx = int(math.Mod(float64(idx), float64(l)))
	   }
	   if v == ints[idx] {
	     matched = append(matched, v)
	   }
	}
	return matched
}

func toInt(s string) []int {
	inputNum := make([]int, len(s))
	i:= 0
	for i < len(s) {
	   inputNum[i], _ = strconv.Atoi(string([]rune(s)[i]))
	   i+=1
	}
	return inputNum
}

func sum(input []int) int {
  s := 0
  for i, _ := range(input) {
    s += input[i]
  }
  return s
}

day2.go

package main

import (
	"fmt"
	"strconv"
	"strings"
)

func main() {
	//input := "5x1x9x5q7x5x3q2x4x6x8q"
	input := "1364x461x1438x1456x818x999x105x1065x314x99x1353x148x837x590x404x123q204x99x235x2281x2848x3307x1447x3848x3681x963x3525x525x288x278x3059x821q280x311x100x287x265x383x204x380x90x377x398x99x194x297x399x87q7698x2334x7693x218x7344x3887x3423x7287x7700x2447x7412x6147x231x1066x248x208q3740x837x4144x123x155x2494x1706x4150x183x4198x1221x4061x95x148x3460x550q1376x1462x73x968x95x1721x544x982x829x1868x1683x618x82x1660x83x1778q197x2295x5475x2886x2646x186x5925x237x3034x5897x1477x196x1778x3496x5041x3314q179x2949x3197x2745x1341x3128x1580x184x1026x147x2692x212x2487x2947x3547x1120q460x73x52x373x41x133x671x61x634x62x715x644x182x524x648x320q169x207x5529x4820x248x6210x255x6342x4366x5775x5472x3954x3791x1311x7074x5729q5965x7445x2317x196x1886x3638x266x6068x6179x6333x229x230x1791x6900x3108x5827q212x249x226x129x196x245x187x332x111x126x184x99x276x93x222x56q51x592x426x66x594x406x577x25x265x578x522x57x547x65x564x622q215x2092x1603x1001x940x2054x245x2685x206x1043x2808x208x194x2339x2028x2580q378x171x155x1100x184x937x792x1436x1734x179x1611x1349x647x1778x1723x1709q4463x4757x201x186x3812x2413x2085x4685x5294x5755x2898x200x5536x5226x1028x180q"

	rows := strings.Split(input, "q")



	rang := make([]int, len(rows))
	var min, max int

	for i, r := range rows {
		row := strings.Split(r, "x")

		for j, s := range(row) {
			n, _ := strconv.Atoi(s)
			if j == 0 {
				min = n
				max = n
			} else {
			
				if n < min {
					min = n
				}
				if n > max {
					max = n
				}
			}
		}
		rang[i] = max - min
		
	}
	
	fmt.Println(sum(rang))
	
}


func sum(input []int) int {
  s := 0
  for i, _ := range(input) {
    s += input[i]
  }
  return s
}