stop allowing repeated elements in priority queues

felipernb · Aug 3, 2014 · fd04111 · fd04111
1 parent b08ebac
commit fd04111
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Showing 2 changed files with 28 additions and 1 deletion.
diff --git a/data_structures/priority_queue.js b/data_structures/priority_queue.js
@@ -11,7 +11,7 @@ function PriorityQueue(initialItems) {
 
   var self = this;
   MinHeap.call(this, function (a, b) {
-    return self._priority[a] < self._priority[b] ? -1 : 1;
+    return self.priority(a) < self.priority(b) ? -1 : 1;
   });
 
   this._priority = {};

diff --git a/test/data_structures/priority_queue.js b/test/data_structures/priority_queue.js
@@ -75,8 +75,35 @@ describe('Min Priority Queue', function () {
     assert.equal(q.extract(), 'e');
     assert.equal(q.extract(), 'c');
     assert.equal(q.extract(), 'd');
+    assert(q.isEmpty());
+  });
+
+  it('should just update the priority when trying to insert an element that ' +
+      ' already exists', function () {
+    var q = new PriorityQueue({
+      a: 10,
+      b: 2091,
+      c: 4,
+      d: 1,
+      e: 5
+    });
 
+    assert(!q.isEmpty());
+
+    q.insert('b', 0);
+    q.insert('a', 1);
+    q.insert('c', 50);
+    q.insert('d', 1000);
+    q.insert('e', 2);
+
+    assert.equal(q.extract(), 'b');
+    assert.equal(q.extract(), 'a');
+    assert.equal(q.extract(), 'e');
+    assert.equal(q.extract(), 'c');
+    assert.equal(q.extract(), 'd');
+    assert(q.isEmpty());
   });
+
 });