leetcode刷題

 來源： https://leetcode.com/problems/valid-parentheses/description

描述

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
Note that an empty string is also considered valid.

Example 1:

Input: "()"
Output: true
Example 2:

Input: "()[]{}"
Output: true
Example 3:

Input: "(]"
Output: false
Example 4:

Input: "([)]"
Output: false
Example 5:

Input: "{[]}"
Output: true

function testF(str)

	local function isFit(strA, strB)
		if strA == '(' and strB == ')' then
			return true;
		end
		if strA == '[' and strB == ']' then
			return true;
		end
		if strA == '{' and strB == '}' then
			return true;
		end
		return false;
	end

	local arr = {}
	for i=1,#str do
		local v = string.sub(str,i,i)
		if #arr == 0 then
			table.insert(arr,v)
		else
			if(isFit(arr[#arr], v) == true) then
				table.remove(arr, #arr)
			end
		end
	end
	if(#arr == 0) then
		print('true')
		return true;
	else
		print('false')
		return false;
	end
end

 

這是lua版本。手頭哪個語言方便，就用哪個語言。