DSA in java

DSA in java

• 1.
  DSA Datastructure and algorithmsfor coding interviews By Saran Kumar R
• 2.
  Apply appropriate datastructurefor efficiency • ArrayList • LinkedList • HashSet • TreeSet • LinkedHashSet • PriorityQueue(heap) • HashMap • TreeMap • LinkedHashMap • Stack • Queue
• 3.
  ArrayList ArrayList<Integer> a=new ArrayList<>(); whento use? • unknown size. • Accessing and retrieving elements
• 4.
  LinkedList LinkedList<Integer> a=new LinkedList<>(); Whento use? • modifications in an list • unknown size
• 5.
  Hash Set HashSet<Integer> a=newHashSet<>(); When to use? • To check if an element exist or not. • To eliminate duplicates.
• 6.
  Tree Set TreeSet<Integer> a=newTreeSet<>(); When to use? • you want elements to be sorted.
• 7.
  LinkedHashSet LinkedHashSet<String> a=new LinkedHashSet<>(); Whento use? • you want to access elements in the inserted order.
• 8.
  PriorityQueue(heap) PriorityQueue<Integer> a=new PriorityQueue<>(); Whento use? • To find kth largest,smallest or most frequent,less frequent elements faster. • Quick sort -> O(nlogn) heap-> O(n)
• 9.
  Hash Map HashMap<String,Integer> a=newHashMap<>(); When to use? • To store in key:value pairs. • Store frequency of elements.
• 10.
  TreeMap TreeMap<Integer,String> a=new TreeMap<>(); Whento use? • When you want keyset to be sorted. a.put(3,”sk”); output: {1=D3, 2=yj, 3=sk, 7=yk} a.put(2,”yj”); a.put(7,”yk”); a.put(1,”D3);
• 11.
  LinkedHashMap LinkedHashMap<Integer,String> a=new LinkedHashMap<>(); Whento use? When you want keyset to be in inserted order. a.put(3,”sk”); output: {3=sk, 2=yj, 7=yk, 1=D3} a.put(2,”yj”); a.put(7,”yk”); a.put(1,”D3);
• 12.
  Stack Stack<Integer> a=new Stack<>(); Whento use? • DFS • Backtracking
• 13.
  Queue Queue<Integer> a=new Queue<>(); Whento use? • BFS • Level order traversal in tree