python - 这个解的时间复杂度是O(logn)吗？

Question

我已经为一个挑战编写了以下解决方案，但我不确定它的时间复杂度:

def ASCIIConversion(string): 
    newStr = ''

    for chr in string:
        if chr.isspace(): 
            newStr = newStr + ' '
        else:
            newStr += str(ord(chr))

    return newStr

程序的复杂度，O(logn)，是不是因为else语句？

Answer 1

最坏情况下的时间复杂度计算如下(假设字符串最大长度为n):

newStr = ''  # will be done once so 1 time.

for chr in string: # is iterating on the input with max length of n so n times.
    if chr.isspace(): # will be checked once it is in the loop so 1 time per each iteration.
        newStr = newStr + ' ' # also once per iteration if the if condition is satisfied
    else: # will be chehcked once per iteration
        newStr += str(ord(chr)) # if else is satisfied

return newStr # will be done 1 time.

我们假设常数时间为 c，所以:

Time complexity = 1 + n(c*c + c*c) + 1 = 2+Cn => O(n)