Software Engineer · Online Assessment · Coding

IBM — Software Engineer

Level: Junior-Level

Round: Online Assessment · Type: Coding · Difficulty: 6/10 · Duration: 60 min · Interviewer: Neutral

Topics: Interval Merging, Arrays, Algorithms

Location: San Francisco Bay Area

Interview date: 2025-12-28

Summary

Round 1: Coding

Question: I was asked to calculate the total execution time of processes given their start and end times, merging overlapping intervals.

Details

Problem Description

The problem involves calculating the total time during which at least one process is running, given a list of processes with their start and end times (inclusive). This requires merging overlapping intervals and summing their lengths.

` class Solution: def getExecutionTime(self, start, end): intervals = sorted(zip(start, end)) merged = []

    for interval in intervals:
        if not merged or interval[0] > merged[-1][1]:
            merged.append(interval)
        else:
            merged[-1] = (merged[-1][0], max(merged[-1][1], interval[1]))

    total_time = 0
    for interval in merged:
        total_time += interval[1] - interval[0] + 1

    return total_time

`

Key points:

• Intervals are inclusive (both start and end times are included).
• You need to merge overlapping intervals.
• Return the sum of all merged interval lengths.
• Time calculation: end - start + 1 (since inclusive).