Amazon | Phone Screen | Job Submission and Selection

Round 1

Questions: You are tasked with managing a set of jobs, each identified by a string ID and associated with a weight. Implement a system where you can submit jobs and select the job with the maximum weight. If a job with the same ID already exists, you should sum up its weight with the new weight provided.

Implement the following two methods:

1. submit(String jobID, int weight)

• Accepts a jobID (string) and weight (integer).
• If the job with the given jobID already exists, add the new weight to the existing weight.
• If the job does not exist, create a new job with the given jobID and weight.

2. select()

• Returns the jobID of the job with the maximum weight.
• If there are multiple jobs with the same maximum weight, return the one that was submitted last.
• If no jobs exist, return null.

Examples:

# Example 1
submit("A", 2)
submit("B", 6)
submit("C", 3)
submit("D", 4)
submit("A", 3)

select()  # Returns "B"
select()  # Returns "A"
select()  # Returns "D"

submit("A", 2)
select()  # Returns "C"
select()  # Returns "A"
select()  # Returns null

# Example 2
submit("X", 10)  # Adds job "X" with weight 10
submit("Y", 5)   # Adds job "Y" with weight 5
submit("Z", 7)   # Adds job "Z" with weight 7
submit("X", 4)   # Updates job "X" by adding weight 4 (total weight of X = 14)
submit("Y", 10)  # Updates job "Y" by adding weight 10 (total weight of Y = 15)
submit("Z", 7)   # Updates job "Z" by adding weight 2 (total weight of Z = 14)

select()  # Returns "Y" weight is 15 
select()  # Returns "X" weight is 14 and was added first
select()  # Returns "Z" weight is 14
select()  # Returns null
select()  # Returns null

Boilerplate Java Code with Class Job and Solution Class JobSolution

import java.util.HashMap;
import java.util.Map;

class Job {
    String jobID;
    int weight;
    
    Job(String jobID, int weight) {
        this.jobID = jobID;
        this.weight = weight;
    }
}

class JobSolution {
    // Submit a job with the given ID and weight.
    public void submit(String jobID, int weight) {
        // Implement this method
    }
    
    // Select the job with the highest weight.
    public String select() {
        // Implement this method
        return null;
    }
}

Candidate's Approach

No approach provided.

Interviewer's Feedback

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Round 2

Questions: Convert String to Integer given very basic constraints that it will fit in the Integer boundaries. Could have negative numbers too. Cannot use existing Parser like Integer.Parse(int).

Candidate's Approach

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Interviewer's Feedback

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