Planting Trees on a Line

You are planting trees along a straight line. Given the positions where existing trees are planted, find out the maximum distance at which you can plant a new tree, such that it is no closer than D distance from any existing trees. Input: - The first line contains the integer T (1 ≤ T ≤ 10^5), the number of existing trees. - The second line contains T space-separated integers representing the positions of the trees. - The third line contains an integer D (1 ≤ D ≤ 10^9), the minimum distance required from existing trees. Output: - A single integer representing the maximum position available for planting a new tree. Example: Input: 5 1 5 10 14 20 2 Output: 22