o(n)时间复杂度替换字符串中空格为%20，字符串,class offer_

o(n)时间复杂度替换字符串中空格为%20，字符串,class offer_

class offer_book:    def replaceBlank( p_str, rpl_str ):        blank = ' '        numOfBlank = 0        originalLen = len( p_str )        for char in p_str:            if char == blank:                numOfBlank += 1        originalIndex = originalLen - 1        newLen = originalLen + numOfBlank * ( len( rpl_str ) - len( blank ) )        newIndex = newLen - 1        newStr = [ blank ] * newLen        while originalIndex >= 0:            if p_str[ originalIndex ] == blank:                newStr[ newIndex ] = '0'                newIndex -= 1                newStr[ newIndex ] = '2'                newIndex -= 1                newStr[ newIndex ] = '%'                newIndex -= 1            else:                newStr[ newIndex ] = p_str[ originalIndex ]                newIndex -= 1            originalIndex -= 1        return str( newStr )newStr = offer_book.replaceBlank( ' we are happy! ', '%20' )print( newStr )