* 199 (N/A - no previous measurement)
+ 200 (increased)
+ 208 (increased)
+ 210 (increased)
- 200 (decreased)
+ 207 (increased)
+ 240 (increased)
+ 269 (increased)
- 260 (decreased)
+ 263 (increased)

with open("input.txt") as f:
    lines = f.readlines()
    numbers = [int(i.strip()) for i in lines]

# create a variable containing the first number for first itration
prev_num = numbers[-1]

# in start result is 0
result = 0

for i in numbers:
    # check if the previous value is lower than the current value, increase count by 1
    if i > prev_num:
        result += 1

    # update the prev_num for the next iteration 
    prev_num = i

print(f"[ part1: {result} ]")

199  A      
200  A B    
208  A B C  
210    B C D
200  E   C D
207  E F   D
240  E F G  
269    F G H
260      G H
263        H

A: 607 (N/A - no previous sum)
B: 618 (increased)
C: 618 (no change)
D: 617 (decreased)
E: 647 (increased)
F: 716 (increased)
G: 769 (increased)
H: 792 (increased)

# in start result is 0
result = 0

size = len(numbers)

# create a variable containing the sum of the first three-measurement sliding window
prev_window = sum(numbers[:3])

# iterate over the size of the depths file 
for i in range(3, size):
    # calculate the current three-measurement sliding window
    curr_window = prev_window + numbers[i] - numbers[i-3]

    # check if the previous value is lower than the current value, increase count by 1
    if prev_window < curr_window:
        result += 1 

    # update the prev_window for the next iteration 
    prev_window = curr_window

print(f"[ part2: {result} ]")