ampIntcode.py

def intcode(file1, phase, inputValue):

    inputCount = 0

    #extract the code from the file and load it into an array for processing
    input1 = open(file1, "r")
    code = input1.read()
    input1.close()
    code = code.split(",")
    for i in range(len(code)):
        code[i] = int(code[i])

    #function to return a five-element array to represent the intcode
    def intcodeArray(int1):
        intcode = list(str(int1))
        if(len(intcode)<5):
            for i in range(5-len(intcode)):
                intcode.insert(0,"0")
        for i in range(len(intcode)):
            intcode[i] = int(intcode[i])
        return intcode

    ##inst[4] and inst[3] are the opcode
    ##inst[2] is the mode of the first parameter
    ##inst[1] is the mode of the second parameter
    ##inst[0] is the mode of the third parameter

    #function to return the value of a position, given its mode
    def value(mode, position):
        val = 0
        if(mode==0):
            val = code[code[position]]
        else:
            val = code[position]
        return val

    pos = 0

    #run the intcode
    while(code[pos]!=99):

        inst = intcodeArray(code[pos])

        #add two values
        if(inst[4]==1):
            two = pos+1
            three = pos+2
            four = code[pos+3]

            code[four] = value(inst[2],two) + value(inst[1],three)
            pos += 4

        #multiply two values
        elif(inst[4]==2):
            two = pos+1
            three = pos+2
            four = code[pos+3]

            code[four] = value(inst[2],two) * value(inst[1],three)
            pos += 4

        #take an input value
        elif(inst[4]==3):

            if(inputCount == 0):
                choice = phase
                inputCount += 1
            else:
                choice = inputValue

            if(inst[2]==0):
                code[code[pos+1]] = choice
            else:
                code[pos+1] = choice

            pos += 2

        #return an output value
        elif(inst[4]==4):
            returnValue = value(inst[2],(pos+1))
            pos += 2

        #if first parameter != 0, jump to position given by the second parameter
        elif(inst[4]==5):

            two = pos+1
            three = pos+2

            if(value(inst[2],two)!=0):
                pos = value(inst[1],three)
            else:
                pos += 3

        #if first parameter is zero, jump to position given by the second parameter
        elif(inst[4]==6):

            two = pos+1
            three = pos+2

            if(value(inst[2],two)==0):
                pos = value(inst[1],three)
            else:
                pos += 3

        #based on whether first parameter < second parameter,
        #store 1 or 0 in the position given by the third parameter
        elif(inst[4]==7):

            two = pos+1
            three = pos+2
            four = code[pos+3]

            if(value(inst[2],two) < value(inst[1],three)):
                code[four] = 1
            else:
                code[four] = 0
            pos += 4

        #based on whether first parameter == second parameter,
        #store 1 or 1 in the position given by the third parameter.
        elif(inst[4]==8):

            two = pos+1
            three = pos+2
            four = code[pos+3]

            if(value(inst[2],two) == value(inst[1],three)):
                code[four] = 1
            else:
                code[four] = 0
            pos += 4

    return returnValue