Dependency Graphs Math Example 3

Solution

1. 1
   Draw the dependency graph: $A$ has no prerequisites; $B$ and $C$ both depend on $A$; $D$ depends on both $B$ and $C$.
2. 2
   Determine stages by levels: Stage 1: $A$ (no dependencies). Stage 2: $B$ and $C$ (both depend only on $A$, so they run in parallel). Stage 3: $D$ (depends on $B$ and $C$, both completed in Stage 2).
3. 3
   The critical path is $A \to B \to D$ (or $A \to C \to D$), each of length 3. So the minimum number of stages is $3$.