RBT(fix): update node values when swapping contents; fixes frptools#44

not-an-aardvark · Jul 10, 2017 · f360416 · f360416
1 parent 7822de0
commit f360416
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diff --git a/packages/red-black-tree/src/internals/ops.ts b/packages/red-black-tree/src/internals/ops.ts
@@ -136,10 +136,12 @@ export function rotateRightLeft<K, V>(upper: PathNode<K, V>, grandParent: Node<K
 export function swapNodeContents<K, V>(upper: Node<K, V>, lower: Node<K, V> /* ## DEV [[ */, tree: RedBlackTreeImpl<K, V> /* ]] ## */): void {
   log(`[swapNodeContents] upper: ${keyOf(upper)}, lower: ${keyOf(lower)}`); // ## DEV ##
   var key = upper.key;
+  var value = upper.value;
   upper.key = lower.key;
   upper.value = lower.value;
 
   lower.key = key;
+  lower.value = value;
   (<any>upper).__flag = 'swap-key'; // ## DEV ##
   (<any>lower).__flag = 'swap-key'; // ## DEV ##
   log(tree, false, `swap node contents; ${upper.key} <==> ${lower.key}`); // ## DEV ##

diff --git a/packages/red-black-tree/tests/functions/remove.ts b/packages/red-black-tree/tests/functions/remove.ts
@@ -38,6 +38,15 @@ suite('[RedBlackTree]', () => {
       }
     });
 
+    test('should not update other keys after a key is removed', () => {
+      var tree = <RedBlackTreeImpl<number, string>>empty();
+      tree = <RedBlackTreeImpl<number, string>>set(1, 'one', tree);
+      tree = <RedBlackTreeImpl<number, string>>set(3, 'three', tree);
+      tree = <RedBlackTreeImpl<number, string>>set(2, 'two', tree);
+      tree = <RedBlackTreeImpl<number, string>>remove(2, tree);
+      assert.strictEqual(get(3, tree), 'three');
+    });
+
     test('should preserve the red-black adjacency invariant required for red-black trees', () => {
       var tree = createTree();
       verifyRedBlackAdjacencyInvariant(tree);