Two Groups Share Exactly N
Two named groups overlap at one or more cells, and exactly N of those shared cells are Innocents. For a row and a column, the intersection is a single cell — so this clue simply pins whether that one cell is Innocent or Suspect. For larger overlapping groups (e.g., a row and a neighborhood), the intersection can contain several cells, and the count of Innocents among them must equal N exactly. Use individual group counts alongside this shared count to constrain the cells that belong to only one of the two groups.
Reading the examples
“Y's neighbors and row 1 share exactly N suspects”
The clue says Alice's neighbors and row 1 share exactly 1 suspect. From the revealed cells, this overlap constraint forces Bob (Suspect).
“The edge and row 1 share exactly N suspects”
The clue says the edge and row 1 share exactly 1 suspect. From the revealed cells, this overlap constraint forces Alice (Innocent), Carol (Innocent).
“The edge and Y's neighbors share exactly N suspects”
The clue says the edge and Eve's neighbors share exactly 2 suspects. From the revealed cells, this overlap constraint forces Grace (Innocent), Henry (Innocent), Iris (Innocent).
“Y's neighbors and Z's neighbors share exactly N suspects”
The clue says Alice's neighbors and Eve's neighbors share exactly 2 suspects. From the revealed cells, this overlap constraint forces Bob (Suspect), Diana (Suspect).
“Y's neighbors and column A share exactly N suspects”
The clue says Alice's neighbors and column A share exactly 1 suspect. From the revealed cells, this overlap constraint forces Diana (Suspect).