LinkedHashMap is a Hash table and linked list implementation of the Map interface. In LinkedHashMap order of key-value pair depends on the order in which keys were inserted into the map. Insertion order does not affect if a key is reinserted into the map.
Example:
Input:
Key: 1
Value : 1221
Key: 2
Value : 2112
Output:
Keys : [1,2]
Values : [1221,2112]
Key-Value pairs : [1=1221, 2=2112]
Methods Use:
- put(Key, Value): First parameter as key and second parameter as Value.
- keySet(): Creates a set out of the key elements contained in the hash map.
- values(): Create a set out of the values in the hash map.
Approach:
- Create two-variable named as Key and Value
- Accept the input from user in Key and in Value
- Use put() method to add Key-Value pair inside the LinkedHashMap
Below is the implementation of the above approach:
Java
// Java Program to add key-value // pairs to LinkedHashMapimport java.util.*;public class Main {        public static void main(String[] args)    {        // create an instance of LinkedHashMap        LinkedHashMap<Integer, Integer> map            = new LinkedHashMap<Integer, Integer>();          int num, key, val;        num = 2;        for (int i = 0; i < num; i++) {                        // Taking inputs from user            key = i + 1;            val = key * 10;              // Add mappings using put method            map.put(key, val);        }        // Displaying key        System.out.println("Keys: " + map.keySet());          // Displaying value        System.out.println("Values: " + map.values());          // Displaying key-value pair        System.out.println("Key-Value pairs: "                           + map.entrySet());    }} |
Output
Keys: [1, 2] Values: [10, 20] Key-Value pairs: [1=10, 2=20]
Time Complexity: O(1)
