Two Sum - Note

Two Sum - LeetCode

First attempt:

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        array = {}
        for i, n in enumerate(nums):
            mediator = target - n
            if mediator in array:
                return [array[mediator], i]
            else:
                return False
        return

- used blank array to use dictionary, mapping. (to not change its default array)

- used enumerate to mark both as differently.

- array dynamically refer to mediator, so it works with/under array's will.

- as hashmap, input key value. i represents each new number from its integer nums. (brute force)

- to state 'otherwise, do not', I return False. Looks like this is the error.

(the purpose was to let program compile as intended. -

in this case: I want to let it roll and scan each value from nums first, then target should substract each value from the beginning until it detects the target value = that match to the sum of its given integer value, nums.)

 

Once I explain this by myself, I realised one thing.

 

If that so...

 

Second attempt:

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        array = {}
        for i, n in enumerate(nums):
            diff = target - n
            if diff in array:
                return [array[diff], i]
            """
            in the array, there is nums,
            and there is new value to take brute force attack 
            for each value to compare and detect the target value.
            
            array OK
            n with array OK
            new value for i OK
            # the goal :
            both target value = the value in array of its integer (each value, brute force)
            array[diff] = i ?
            Miss! that process was compilled already above.
            array[nums] = i ?
            """
            array[n] = i
        return

 

Time spending : 53 mins.

Tip: write down my understanding somewhere in a plain English, then try code it based on its info.

 

referred:

https://stackoverflow.com/questions/9197324/what-is-the-meaning-of-curly-braces#:~:text=In%20languages%20like%20C%20curly,used%20to%20define%20program%20blocks.

What is the meaning of curly braces?

https://www.geeksforgeeks.org/hash-map-in-python/