80 lines
2.3 KiB
Python
80 lines
2.3 KiB
Python
#!/usr/bin/python3
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diagram = []
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totalPoints = 0
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# Read all the line segments into an array.
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segments = []
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with open('/home/jake/Documents/AoC-2021/Day-5/input.txt') as inputFile:
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for line in inputFile:
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segment = line.strip('\n').split(' -> ')
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segments.append(segment)
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# Work out the bounds of our diagram and create an array for it.
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largestX = 0
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largestY = 0
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for segment in segments:
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if(int(segment[0].split(',')[0]) > largestX):
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largestX = int(segment[0].split(',')[0])
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if(int(segment[1].split(',')[0]) > largestX):
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largestX = int(segment[1].split(',')[0])
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if(int(segment[0].split(',')[1]) > largestY):
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largestY = int(segment[0].split(',')[1])
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if(int(segment[1].split(',')[1]) > largestX):
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largestY = int(segment[1].split(',')[1])
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for i in range(0, largestY+1):
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diagLine = []
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for i in range(0,largestX+1):
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diagLine.append(0)
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diagram.append(diagLine)
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# Run through the line segments and plot them on the diagram.
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for segment in segments:
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startingX = int(segment[0].split(',')[0])
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startingY = int(segment[0].split(',')[1])
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endingX = int(segment[1].split(',')[0])
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endingY = int(segment[1].split(',')[1])
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# Create lists for the X and Y points our lines will go through.
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if(startingX > endingX):
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xStep = -1
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endingX-=1
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else:
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xStep = 1
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endingX+=1
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if(startingY > endingY):
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yStep = -1
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endingY-=1
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else:
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yStep=1
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endingY+=1
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xList = list(range(startingX, endingX, xStep))
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yList = list(range(startingY, endingY, yStep))
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# If the line is horizontal or vertical there will be differing numbers of indexes so we need to loop though them separately.
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if(len(xList) != len(yList)):
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for x in xList:
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for y in yList:
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diagram[y][x]+=1
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# Otherwise they will be identical and we need to increment both lists together.
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else:
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for i in range(0, len(xList)):
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currentX = xList[i]
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currentY = yList[i]
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diagram[currentY][currentX]+=1
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# Find points where two or more line segments overlap.
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for line in diagram:
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for num in line:
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if(num > 1):
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totalPoints+=1
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# Print the results.
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print("There are " + str(totalPoints) + " points where two or more lines overlap.")
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