Disclosed are a method and system for optimized, dynamic data-dependent program execution. The disclosed system comprises a statistics computer which computes statistics of the incoming data at the current time instant, where the said statistics include the probability distribution of the incoming data, the probability distribution over program modules induced by the incoming data, the probability distribution induced over program outputs by the incoming data, and the time-complexity of each program module for the incoming data, wherein the said statistics are computed on as a function of current and past data, and previously computed statistics; a plurality of alternative execution path orders designed prior to run-time by the use of an appropriate source code; a source code selector which selects one of the execution path orders as a function of the statistics computed by the statistics computer; a complexity measurement which measures the time-complexity of the currently selected execution path-order.