Problem
Objective
We're learning about Key Value pair mappings using a Map or Dictionary data structure. Check out the Tutorial tab for learning at HackerRank Tutorial
Task
Given n names and phone numbers, assemble a phone book that maps friends names to their respective phone numbers. You will then be given an unknown number of names to query your phone book for. For each name queried, print the associated entry from your phone book on a new line in the form name=phone Number If an entry for name is not found, print Not found instead.
Note: Your phone book should be a Dictionary/Map/HashMap data structure.
Input Format
The first line contains an integer, denoting the number of entries in the phone book.
Each of the n subsequent lines describes an entry in the form of 2 space-separated values on a single line. The first value is a
friend's name, and the second value is an 8-digit phone number,
After the n lines of phone book entries, there are an unknown number of lines of queries. Each line (query) contains a name to
look up, and you must continue reading lines until there is no more input
Note: Names consist of lowercase English alphabetic letters and are first names only
Constraints
• 1<n< 10^5
• 1< queries < 10^5
Output Format
On a new line for each query, print Not found if the name has no corresponding entry in the phone book: otherwise, print the full name and phone Number in the format name=phone Number.
Sample input
sam 99912222
tom 11122222
harry 12299933
sam
edward
harry
Sample Output
sam=99912222
Not found
harry-12299933
Explanation
We add the following n = 3 (Key Value) pairs to our rap so it looks like this phone Book = {(sam, 99912222) (tom, 11122222) (harry, 12299933) } We then process each query and print key=value if the queried key is found in the map otherwise, we print Not found.
Query 0: sam
Sam is one of the keys in our dictionary, so we print sam-99912222
Query 1: edward
Edward is not one of the keys in our dictionary, so we print Not found.
Query 2 : harry
Harry is one of the keys in our dictionary, so we print harry=12299933
Recommended: Please try your approach on your integrated development environment (IDE) first, before moving on to the solution.
Few words from CodingHumans : Don't Just copy paste the solution, try to analyze the problem and solve it without looking by taking the the solution as a hint or a reference . Your understanding of the solution matters.
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Solution:
(java)
import java.util.*;
import java.io.*;
class Solution{
public static void main(String []argh){
Scanner in = new Scanner(System.in);
Map<String,Integer> Contact =new HashMap<String,Integer>();
int n = in.nextInt();
for(int i = 0; i < n; i++){
String name = in.next();
int phone = in.nextInt();
Contact.put(name,phone);
}
while(in.hasNext()){
String s = in.next();
if(Contact.containsKey(s)){
System.out.println(s+"="+Contact.get(s));
}
else{
System.out.println("Not found");
}
}
in.close();
}
}
