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  1. Prepare
  2. Data Structures
  3. Arrays
  4. Arrays - DS
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Arrays - DS

  • emhhacker
     + 1 comment

    My Java soluton with o(n) time complexity and o(1) space complexity:

    public static List<Integer> reverseArray(List<Integer> a) {
        // use a pointer at the start and the end
        //flip while the left pointer is less than the right pointer
        int left = 0, right = a.size() - 1;
        while(left < right){
            int leftVal = a.get(left);
            int rightVal = a.get(right);
            a.set(left, rightVal);
            a.set(right, leftVal);
            left++;
            right--;
        }
        return a;
    }