Brad's AOC2018 Problem 3b

feedback.py

linelist = f.readlines() # readlines makes a list of each line...  linelist is an array
listnum = len(linelist) # listnum is the number of lines

# Creates a map of dimensions init x init with all zeroes in it.  Double Array
init = 1100  # Map size
map = []

### Minor performance penalty for the first non-nested loop.
'''
for row in range(init):
    for col in range(init):
        newRow = []
        newRow.append(0)
    map.append(newRow)
'''
for row in range(init):
    map.append([])
for row in map:
    for col in range(init):
        row.append(0)

# Go through the list and put the number of the item in each coordinate
### A real gangsta would use regular expressions for this
### https://www.youtube.com/watch?v=ZdDOauFIDkw (21min tutorial)
for line in linelist:
    num = int(line[1:line.index("@")])
    startx = int(line[line.index("@")+2:line.index(",")])
    starty = int(line[line.index(",")+1:line.index(":")])
    lenx = int(line[line.index(":")+2:line.index("x")])
    leny = int(line[line.index("x")+1:-1])

    for x in range(lenx):
        for y in range(leny):
            map[starty + y][startx + x] += num

# Go through the list and see if the number in the cell is the original
### Don't parse these again; those string ops are expensive
### Make function that parses a single claim into a datastructure (dictionary would be perfect)
### Then in your setup phase loop through the original list of lines
### once saving a new list of parsed claims.
### See also the map function https://youtu.be/Z8Cu-8brldc?t=78 (2min example)
for line in linelist:
    num = int(line[1:line.index("@")])
    startx = int(line[line.index("@") + 2:line.index(",")])
    starty = int(line[line.index(",") + 1:line.index(":")])
    lenx = int(line[line.index(":") + 2:line.index("x")])
    leny = int(line[line.index("x") + 1:-1])

    ### out = False? Then I know immediately that it's a flag
    ### out = 0 makes me think you're about to count something.
    out = 0
    for x in range(lenx):
        for y in range(leny):
            if map[starty + y][startx + x] != num:
                out = 1
    if out == 0:

        print(num)