Simple java solution
\n\n# Complexity\n- Time complexity: O(n)\n\n- Space complexity: O(1)\n\n# Code\n\nclass Solution {\n    public long findTheArrayConcVal(int[] nums) {\n        
\n\n# Complexity\n- Time complexity: $$O(n)$$\n\n- Space complexity: $$O(1)$$\n\n# Code\n```\nclass Solution {\n    public long findTheArrayConcVal(int[] nums) {\n        long m=0;\n        if(nums.length==1)\n        {\n            return (long)(nums[0]);\n        }\n        for(int i=0,j=nums.length-1;i<j;i++,j--)\n        {\n            String p=String.valueOf(nums[i])+String.valueOf(nums[j]);\n            long q=Long.parseLong(p);\n            m+=q;\n        }\n        if(nums.length%2==1)\n        {\n            return m+(long)(nums[nums.length/2]);\n        }\n        return m;\n    }\n}\n```
['Java']