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--- java_primer [2020/08/20 15:22] – [PriorityQueue] jrseti
+++ java_primer [2020/11/19 17:19] (current) – [LinkedHashMap] jrseti
@@ Line 17: / Line 17: @@
   * But, **keys are ordered**!
   * No null keys
+  * keySet()and values() return in ascending order
 ====LinkedHashMap====
+**An OrderedDict!**
 Same as hashMap but preserves **insertion order**. O(1) insertion and lookup.
@@ Line 139: / Line 142: @@
 }
-PriorityQueue<String> queue = new
+PriorityQueue<String> queue = new PriorityQueue<String>(new The_Comparator());
-PriorityQueue<String>(new The_Comparator());
 </code>
@@ Line 162: / Line 164: @@
   * LinkedList is better with add(), remove.
   * ArrayList better with get(), set().
+  * Char to digit: s.charAt(num2Idx) - '0'
+=====TRICKS=====
+====Log and division====
+  * a / b = Math.exp(Math.log(a) - Math.log(b))
+====Random====
+<code>
+//Random number from 0 to 5
+Random rand = new Random();
+int r = rand.nextInt(6);
+</code>
+or
+<code>
+//Number between 0.0 and 1.0;
+Math.random();
+</code>