diff --git a/index.html b/index.html
index f7218eb611d5353d46c6a22381d35c5682c5bbee..0e334b31d564a91255396fb7f88b4d69a59222fb 100644
--- a/index.html
+++ b/index.html
@@ -9,7 +9,8 @@
</head>
<body>
- <div id="result"></div>
+ <div id="time"></div>
+ <div id="freeness"></div>
<script src="libraries/jquery/jquery.min.js"></script>
<script src="js/hash_table.js"></script>
<script src="js/words.js"></script>
diff --git a/js/hash_table.js b/js/hash_table.js
index fb3a37c30961eac5eb3804fbb24a66c1c6bf5de1..37c78d2c7091e17404f35b20fde47009186c4b00 100644
--- a/js/hash_table.js
+++ b/js/hash_table.js
@@ -60,6 +60,19 @@ class HashTable {
return this._size;
}
+ get collisionFreeness() {
+ if (this._size === 0) {
+ return 1.0;
+ }
+ let occupiedBucketCount = 0;
+ for (const bucket of this._buckets) {
+ if (bucket.length > 0) {
+ ++occupiedBucketCount;
+ }
+ }
+ return occupiedBucketCount / this._size;
+ }
+
has(element) {
return this._buckets[this._hashFunction(element)].includes(element);
}
@@ -68,10 +81,10 @@ class HashTable {
const bucket = this._buckets[this._hashFunction(element)];
if (!bucket.includes(element)) {
bucket.push(element);
- }
- ++this._size;
- if (this._size / this._buckets.length > MAXIMUM_LOAD_FACTOR) {
- this._resize();
+ ++this._size;
+ if (this._size / this._buckets.length > MAXIMUM_LOAD_FACTOR) {
+ this._resize();
+ }
}
}
diff --git a/js/index.js b/js/index.js
index d85099f7d84ff8599e34a5fdea779e2f4e0cc1d9..cc6a5c383acb3822e93c612998acf11958391231 100644
--- a/js/index.js
+++ b/js/index.js
@@ -4,11 +4,19 @@
const startTime = Date.now();
-const table = new HashTable((word) => 0);
+const table = new HashTable((word) => 0); // TODO: Design a better hash function
+
for (const word of DICTIONARY) {
table.add(word);
}
+for (const word of DICTIONARY) {
+ if (!table.has(word)) {
+ throw new Error(`Found an inconsistency in the hash function when applying it to "${word}"`);
+ }
+}
+
const endTime = Date.now();
-$('#result').text(`Constructed hash table of American English words in ${endTime - startTime} ms.`);
+$('#time').text(`Constructed and verified a hash table of American English words in ${endTime - startTime} ms.`);
+$('#freeness').text(`Collision freeness using this hash function: ${(100 * table.collisionFreeness).toFixed(3)}%.`);