「世界で闘うプログラミング力を鍛える本」Pythonコード解答例 - 1.3 URLify

#目次
###CHAP1. 配列と文字列

#Pythonコード解答例

def replaceSpaces(str,trueLength):

    spaceCount = 0

    for i in range(trueLength):
        if str[i] == " ":
            spaceCount = spaceCount + 1

    index = trueLength + spaceCount * 2

    target = [0] * index

    for i in range(trueLength-1,-1,-1):

        if str[i] == " ":
            target[index-1] = "0"
            target[index-2] = "2"
            target[index-3] = "%"
            index = index - 3

        else:
            target[index-1] = str[i]
            index = index - 1

    return "".join(target)

input_str = "Mr John Smith"
input_num = len(input_str)

print(replaceSpaces(input_str,input_num))