Singleton

lintcode:

http://lintcode.com/en/problem/singleton/

Java

class Solution {
    
    public static Solution instance = null;
    
    /**
     * @return: The same instance of this class every time
     */
    public static Solution getInstance() {
        // write your code here
        if (instance == null) {
            instance = new Solution();
        }
        return instance;
    }
};

Python

class Solution:
    
    instance = None
    
    # @return: The same instance of this class every time
    @classmethod
    def getInstance(cls):
        # write your code here
        if cls.instance == None:
            cls.instance = Solution()
            
        return cls.instance