A Game of Robots

You've built some robots and placed them on an one dimensional grid with $n$ cells. Their arrangement is given by a string $s$ of length $n$. Each character of the string is either '.' or a digit in the range '0' to '9'. A '.' represents that there is no robot at that cell initially. A digit represents a robot initially in that cell. Specifically, the digit $x$ denotes that the range of the robot