Find Maximum Chain Activations

You are given `n` devices, where each device is represented as `[x, y, r]`. Device `i` is located at coordinates `(x, y)` and can directly activate device `j` if the Euclidean distance between them is less than or equal to `r_i`. Activation is directional: device `i` may be able to activate device `j` even when `j` cannot activate `i`. If you manually activate exactly one device first, every device reachable from it, directly or indirectly, will also become activated. Return the maximum number of devices that can be activated by choosing the best starting device. Also explain the time and space complexity of your approach.