ARTS-week10

Posted 2021-03-14 felixqiang

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Algorithm

判断一个整数是否是回文数。回文数是指正序（从左向右）和倒序（从右向左）读都是一样的整数。

class Solution:
    # 解1,时间复杂度O(n)
    def isPalindrome1(self, x: int) -> bool:
        return str(x) == str(x)[::-1]
    
    # 解2，时间复杂度O(log10(n))
    def isPalindrome2(self, x: int) -> bool:
    if x < 0 or (x % 10 == 0 and x != 0):
        return False
        
    revertedNumber = 0
    while x > revertedNumber:
        revertedNumber = x % 10 + revertedNumber * 10
        x //= 10
        
        return (x == revertedNumber // 10) or (x == revertedNumber)

罗马数字包含以下七种字符:?I，?V，?X，?L，C，D?和?M。

给定一个罗马数字，将其转换成整数。输入确保在 1?到 3999 的范围内。
Roman to Integer

class Solution:
    # 解1，时间复杂度O(n)
    def romanToInt(self, s: str) -> int:
        roman_dir = {"I":1,"V":5,"X":10,"L":50,"C":100,"D":500,"M":1000}
        sum = roman_dir[s[-1]]
        for i in range(len(s)-1):
            if roman_dir[s[i]] >= roman_dir[s[i+1]]:
                sum += roman_dir[s[i]]
            else:
                sum -= roman_dir[s[i]]
        return sum

Review

Learn Vim Progressively

作者将学习VIM分成4个阶段，分别是

Survive
Feel comfortable
Feel Better, Stronger, Faster
Use superpowers of vim
从浅入深，非常适合用于学习vim用，按照作者的话说，“
By the end of this journey, you’ll become a vim superstar.”:)