Adding shortcut to NAND clause in 2-SAT code.

1 files changed, 1 insertions, 0 deletions

diff --git a/graph/2sat.cpp b/graph/2sat.cpp
index bc1572d..99df78c 100644
--- a/graph/2sat.cpp
+++ b/graph/2sat.cpp
@@ -19,6 +19,7 @@ struct sat2 {
 	void addTrue(int v1) { addImpl(1^v1, v1); }
 	void addFalse(int v1) { addTrue(1^v1); }
 	void addAnd(int v1, int v2) {	addTrue(v1); addTrue(v2); }
+	void addNand(int v1, int v2) { addOr(1^v1, 1^v2); }
 
 	void dfs(int v) {
 		visited[v] = true;