VLSI DV Interview Puzzles · All levels
Constraint Solving Order Puzzles
Count legal tuples first, then reason about bias: implication and if/else are declarative relations solved together, and branch cardinality drives observed probabilities.
About this puzzle set
Count legal tuples first, then reason about bias: implication and if/else are declarative relations solved together, and branch cardinality drives observed probabilities.
Puzzles in this topic
diagram
1. Implication vs Partitioned Branches [Medium]
2. Bidirectional Solving of x+y==10 [Easy]
3. if-else with Overlap on One Value [Medium]
4. Three-Variable Implication Chain [Hard]
5. Relational Pair Counting [Medium]
6. Array Size Coupled to Content [Hard]Work each puzzle before reading the solution: predict the exact output or answer, name the rule that governs it, then check yourself.
Constraint solve order and dependency flow
diagram
CONSTRAINT SOLVE ORDER
rand bit [3:0] burst_len;
rand bit [7:0] addr;
constraints:
burst_len inside {[1:8]};
addr % burst_len == 0;
solve burst_len before addr;
solver picks burst_len first
then chooses addr satisfying alignment
Explicit solve order reduces ambiguity in interview puzzles.