Advent of Code - adventofcode.com

Thanks

Yep, that makes a lot of sense. Found the same thing in a different language looking at the Reddit solution thread so at least I did the Python implementation myself. Will no doubt be tough going, but that's what I'm doing it for.

expense_list = [int(line) for line in open('day1_input.txt', 'r')]
solved1 = False
solved2 = False

for e in expense_list:
    lookup1 = 2020 - e
    if lookup1 in expense_list:
        print(e * lookup1)
        solved1 = True
        
    for f in expense_list:
        lookup2 = lookup1 - f
        if lookup2 in expense_list:
            print(e * f * lookup2)
            solved2 = True
            
    if solved1 & solved2:
        finishtime = datetime.now()
        print(finishtime)
        exit()

I suppose this is also the moment to familiarize myself with Git so I'm no longer making a mess with codeblocks in this thread.

How come you used a dictionary with all values of 1, rather than a list or a set?

And now it's my python version too.

Congratulations - you have now become my python tutor!

I did this in bash - because box of hammers, and I didn't want to suffer the ignominy of doing it in excel or vba.

#!/bin/bash
# Advent of Code - Day 1, Puzzle 1
inputfile=$1
# numbercount=$(cat $1 | wc -l) # Edit because numbers
numbercount=$(( $(cat $1 | wc -l) + 1 ))
start=$SECONDS
for ((i = 1 ; i < $numbercount ; i++)); do
    for ((j = $i + 1 ; j < $numbercount ; j++)); do
        ivalue=$(awk "NR == $i" $inputfile)
        jvalue=$(awk "NR == $j" $inputfile)
        if [[ $(( $ivalue + $jvalue )) -eq 2020 ]] ; then
            echo "$ivalue + $jvalue = $(( $ivalue + $jvalue )), $ivalue * $jvalue = $(( $ivalue * $jvalue ))" 
        fi
    done
done
duration=$(( SECONDS - start ))
echo $duration

 :: tiswas@laptop2:/home/tiswas/Temp :: 
 $ ./sum_to_2020.sh input1.txt 
1632 + 388 = 2020, 1632 * 388 = 633216
76 seconds 19900 records

Seeing working python code for this is useful though, as I'm learning that from scratch at the moment.

[Edit] because missing a number in the loop