Techniques are described for advertising constraint-based path computation (e.g., flexible-algorithm) through a constrained network topology. For example, a network device comprises a memory and one or more programmable processors operably coupled to the memory, wherein the one or more programmable processors are configured to generate a packet including a segment identifier (SID) offset, wherein the SID offset is an offset value associated with the flexible-algorithm. The one or more programmable processors of the network device are also configured to send, to at least one other network device of the plurality of network devices, the SID offset to enable the at least one other network device to derive a node segment identifier for the at least one other network device to participate in the flexible-algorithm.