fix: updated two-sat interfaces

Author: a1fredbao

src/alfred/all

@@ -24,6 +24,7 @@
 
 #include "graph/graph.hpp"
 #include "graph/grid.hpp"
+#include "graph/twosat.hpp"
 #include "graph/hld.hpp"
 #include "graph/lca.hpp" // Will be included after graph class is implemented well enough
 #include "graph/maxflow.hpp"

src/alfred/graph/twosat.hpp

@@ -6,7 +6,7 @@
 struct TwoSAT {
     std::vector<std::vector<int>> G;
     std::vector<int> dfn, low, stk, bel, in;
-    TwoSAT(void) = default;
+    // TwoSAT(void) = default;
     TwoSAT(int n) : G(2 * n) {}
     void tarjan(int u, int &cnt, int &cc) {
         dfn[u] = low[u] = ++cnt;
@@ -30,11 +30,32 @@ struct TwoSAT {
     }
     // Add constraint: x = a or y = b.
     inline void add(int x, bool a, int y, bool b) {
-        size_t should = 2 * (std::max(x, y) + 1);
-        if (G.size() < should) G.resize(should);
+        // size_t should = 2 * (std::max(x, y) + 1);
+        // if (G.size() < should) G.resize(should);
         G[x << 1 | !a].push_back(y << 1 | b);
         G[y << 1 | !b].push_back(x << 1 | a);
     }
+    // Add constraint: x = a => y = b;
+    inline void conduct(int x, bool a, int y, bool b) {
+        // size_t should = 2 * (std::max(x, y) + 1);
+        // if (G.size() < should) G.resize(should);
+        G[x << 1 | a].push_back(y << 1 | b);
+    }
+    inline void same(int x, int y) {
+        conduct(x, true, y, true);
+        conduct(y, true, x, true);
+        conduct(x, false, y, false);
+        conduct(y, false, x, false);
+    }
+    inline void diff(int x, int y) {
+        conduct(x, true, y, false);
+        conduct(y, true, x, false);
+        conduct(x, false, y, true);
+        conduct(y, false, x, true);
+    }
+    inline void set(int x, bool v) {
+        conduct(x, !v, x, v);
+    }
     inline void init(void) { // find scc.
         int n = G.size(), cnt = 0, cc = 0;
         in = dfn = low = bel = std::vector<int>(n, 0);