【LeetCode】0065&剑指Offer20 有效数字&表示数值的字符串

https://leetcode-cn.com/problems/valid-number/

https://leetcode-cn.com/problems/biao-shi-shu-zhi-de-zi-fu-chuan-lcof/

# -*- coding:utf-8 -*-

class Solution(object):
    def isNumber(self, s):
        """
        :type s: str
        :rtype: bool
        """
        try:
            float(s)
            return True
        except:
            return False
if __name__ == '__main__':
    s = '5e4'
    print(float(s))
    print(Solution().isNumber(s))

思路：硬取巧。

这道题的正规思路应该是状态机，类似于设计模式中的状态机，维护一个状态的二维数组，表示当当前状态是i时，下一个状态是j时应该输出的状态。每次读取一个字符，依次向后判断。

	// 数字，指数，正负，小数点，空格，其他字符
	// 0	 1    2	   3	 4       5
		{1, 10, 8, 11, 0, 10},
		{1, 3, 10, 2, 6, 10},
		{7, 3, 10, 10, 6, 10},
		{5, 10, 4, 10, 10, 10},
		{5, 10, 10, 10, 10, 10},
		{5, 10, 10, 10, 6, 10},
		{10, 10, 10, 10, 6, 10},
		{7, 3, 10, 10, 6, 10},
		{9, 10, 10, 11, 10, 10},
		{9, 3, 10, 2, 6, 10},
		{10, 10, 10, 10, 10, 10},
		{7, 10, 10, 10, 10, 10},