cl-interpret: References, part 3

MODS ARE ASLEEP
POST FAT BEAGLE

sample-code/unionfind.cl

@@ -0,0 +1,69 @@
+//! Disjoint Set Forest implementation of the Union Find algorithm
+
+// enum TreeNode {
+//     Empty,
+//     Filled { parent: usize, rank: usize }
+// }
+
+// TODO: Namespace based on type of first argument
+
+fn makeset(f, x) {
+    match (*f)[x] {
+        () => (*f)[x] = Filled { parent: x, rank: 0 },
+        _ => {}
+    }
+}
+
+fn union(f, a, b) {
+    let (a, b) = (find(f, a), find(f, b));
+    if a == b { return; }
+    match ((*f)[a], (*f)[b]) {
+        (Filled {parent: _, rank: r_a}, Filled {parent: _, rank: r_b}) => {
+            if r_a < r_b {
+                union(f, b, a)
+            } else {
+                (*f)[b].parent = a;
+                (*f)[a].rank += 1;
+            }
+        }
+    }
+}
+
+fn find(f, x) {
+    match (*f)[x] {
+        Filled { parent, rank } => if parent == x {
+            x
+        } else {
+            let parent = find(f, parent);
+            (*f)[x].parent = parent;
+            parent
+        },
+        () => x,
+    }
+}
+
+fn show(f) {
+    for node in 0..(len((*f))) {
+        match (*f)[node] {
+            Filled { parent, rank } => println(node, ": { parent: ", parent, ", rank: ", rank, " }"),
+            _ => {}
+        }
+    }
+}
+
+fn test(f) {
+    "Union Find on Disjoint Set Forest".println()
+    for i in 0..10 { makeset(f, i) }
+    for i in 10..20 { makeset(f, i) }
+    show(f)
+    println()
+    
+    for i in 1..10 { union(f, i*2-1, i*2) }
+    for i in 5..10 { union(f, i*2+1, i*2) }
+    show(f)
+}
+
+fn main() {
+    let f = [();20]
+    f.test()
+}