Data commit

Task/N-queens-problem/Picat/n-queens-problem-1.picat

@@ -0,0 +1,23 @@
+import sat.
+% import mip.
+
+queens_sat(N,Q) =>
+  Q = new_array(N,N),
+  Q :: 0..1,
+
+  foreach (K in 1-N..N-1)
+    sum([Q[I,J] : I in 1..N, J in 1..N, I-J==K]) #=< 1
+  end,
+
+  foreach (K in 2..2*N)
+    sum([Q[I,J] :  I in 1..N, J in 1..N, I+J==K]) #=< 1
+  end,
+
+  foreach (I in 1..N)
+    sum([Q[I,J] : J in 1..N]) #= 1
+  end,
+
+  foreach (J in 1..N)
+    sum([Q[I,J] : I in 1..N]) #= 1
+  end,
+  solve([inout],Q).

Task/N-queens-problem/Picat/n-queens-problem-2.picat

@@ -0,0 +1,9 @@
+import cp.
+
+queens(N, Q) =>
+   Q = new_list(N),
+   Q :: 1..N,
+   all_different(Q),
+   all_different([$Q[I]-I : I in 1..N]),
+   all_different([$Q[I]+I : I in 1..N]),
+   solve([ff],Q).

Task/N-queens-problem/Picat/n-queens-problem-3.picat

@@ -0,0 +1,9 @@
+queens_naive(N, Q) =>
+  Q = new_list(N),
+  Q :: 1..N,
+  foreach(I in 1..N, J in 1..N, I < J)
+    Q[I] #!= Q[J],
+    Q[I] + I #!= Q[J] + J,
+    Q[I] - I #!= Q[J] - J
+  end,
+  solve([ff], Q).