@@ -3,10 +3,12 @@ const HashEntry = require('./HashEntry');
33class HashTable {
44 constructor ( slots ) {
55 // init with a default set of slots
6- this . slot = slots || 17 ;
6+ this . slot = slots || 19 ;
77 // size to hold the current size
88 // and help to resize when the table is half filled
99 this . size = 0 ;
10+ // threshold (let it be 70%)
11+ this . threshold = 0.7 ;
1012 // the main bucket
1113 this . bucket = new Array ( this . slot ) ;
1214
@@ -32,6 +34,34 @@ class HashTable {
3234 return index ;
3335 }
3436
37+ _resize ( ) {
38+ const oldSlot = this . slot ;
39+ const oldBucket = this . bucket ;
40+ 41+ this . slot = oldSlot * 2 ;
42+ const newBucket = new Array ( this . slot ) ;
43+ // fill the new bucket with nulls
44+ for ( let i = 0 ; i < this . slot ; i += 1 ) newBucket [ i ] = null ;
45+ 46+ this . bucket = newBucket ;
47+ 48+ for ( let i = 0 ; i < oldSlot ; i += 1 ) {
49+ if ( oldBucket [ i ] ) {
50+ // get all the nodes associated here
51+ let head = oldBucket [ i ] ;
52+ 53+ while ( head !== null ) {
54+ const { key, value } = head ;
55+ // eslint-disable-next-line no-underscore-dangle
56+ const newIndex = this . _hash ( key ) ;
57+ // eslint-disable-next-line no-underscore-dangle
58+ this . _push ( newIndex , { key, value } ) ;
59+ head = head . next ;
60+ }
61+ }
62+ }
63+ }
64+ 3565 _push ( index , value ) {
3666 /**
3767 * Util to add a SSL to the index in case of more than once
@@ -76,6 +106,17 @@ class HashTable {
76106 // storing value as an key-value pair
77107 // eslint-disable-next-line no-underscore-dangle
78108 this . _push ( index , { key, value } ) ;
109+ 110+ /**
111+ * calculate the load factor, if it's greater than threshold
112+ * resize the hash table
113+ */
114+ const loadFactor = ( this . size / this . slot ) . toFixed ( 1 ) ;
115+ if ( loadFactor > this . threshold ) {
116+ // console.log('Resizing hash table');
117+ // eslint-disable-next-line no-underscore-dangle
118+ this . _resize ( ) ;
119+ }
79120 }
80121
81122 get ( key ) {
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