# Day2¶

Solution to day 1 of Advent of Code https://adventofcode.com/2018/day/2

## Part 1¶

Making use of Counter from collections to count the number of occurences of each letter.

In [1]:

```
from collections import Counter
a, b = 0,0
with open('datafiles/aoc2input.txt','r') as f:
for line in f.readlines():
c = Counter(line)
if 2 in c.values():
a+=1
if 3 in c.values():
b+=1
print(a*b)
```

## Part 2¶

Testing all combinations with combinations from itertools, each combination is tested by zipping two strings together and summing over differences. We make use of True evaluating to 1 and False evaluating to 0 when summing.

In [2]:

```
from itertools import combinations
with open('datafiles/aoc2input.txt','r') as f:
lines = f.readlines()
for a,b in combinations(lines, 2):
if sum(i != j for i, j in zip(a, b)) == 1:
print("".join(i for i,j in zip(a,b) if i==j ))
break
```