O(sumof(n)) 时间复杂度

Question

问题简单明了：有没有时间复杂度

这是正确的写法吗？我问是因为我写的这个程序：

    def check(self, front, s, back):
        if(s[front:back] == s[front:back][::-1]): 
            return s[front:back]
        else: 
            return self.check(front, s, back-1)

    def checkIter(self, front, s, back, longest):
        r = self.check(front, s, back)
        if(len(r) >= len(longest)): longest = r
        if(front < back):
            return self.checkIter(front+1,s,back, longest)
        else:
            return longest
        
    def longestPalindrome(self, s):
        """
        :type s: str
        :rtype: str
        """
        return self.checkIter(0,s,len(s),"")

在 longestPalindrome('cbbd') 的输入上它运行 ~10 次产生输出：

"cbbd" "cbb" "cb" "c" "bbd" "bb" "b" "bd" "b" "d"。在 longestPalindrome('cbbda') 的类似输入上给出： "cbbda" "cbbd" "cbb" "cb" "c" "bbda" "bbd" "bb" "b" "bda" "bd" "b" "da" "d" "a" 所以这不可能是 O(n)

Answer 1

指定的总和等于n(n+1)/2。因此，它在 O(n^2).

O(sumof(n)) 时间复杂度

O(sumof(n)) time complexity

algorithm

complexity-theory

big-o

time-complexity