Python Short and Simple
Solution \n\nI use a left and right pointer and increment my answer at each step of the time, by concatenating the two numbers in their string form and converti
# Solution \n\nI use a left and right pointer and increment my answer at each step of the time, by concatenating the two numbers in their string form and converting back to int. If the middle element is left (or if $N$ is odd), simply add it to the answer. \n\nAlternatively, you can just simulate what is stated in the problem. For languages like C++ where vector.erase(0) works in $O(N)$, you could use a deque or similar data structure, although it is not necessary, as $O(N^2)$ passes under the small constraints.  \n\n# Complexity\n- Time complexity: $O(N)$\n- Space complexity: $O(1)$ (extra space)\n\n### \n\n```py\nclass Solution:\n    def findTheArrayConcVal(self, nums: List[int]) -> int:\n        l = 0\n        r = len( nums)-1 \n        ans = 0 \n        \n        while (l < r): \n            x = str( nums[l]) \n            y = str( nums[r]) \n            x += y \n            ans += int(x)\n            l += 1\n            r -= 1 \n            \n        if l == r: \n            ans +=  nums[l] \n        \n        return ans\n```
['Python3']