The Merge Intervals pattern is commonly used in coding interviews to solve problems involving overlapping or merging intervals. It's particularly useful when dealing with problems related to scheduling, time intervals, or event management. Let me explain the pattern and provide you with an example question and its solution.

Pattern: Merge Intervals

1. Sort the intervals based on their start time.
2. Create an empty result list to store the merged intervals.
3. Initialize the first interval from the sorted list as the current interval.
4. Iterate through the remaining intervals.
   • If the current interval and the next interval overlap, merge them by updating the end time of the current interval.
   • If they don't overlap, add the current interval to the result list and update the current interval to the next interval.
5. After the iteration, add the last current interval to the result list.

Now, let's see an example question and its solution using the Merge Intervals pattern.

Example Question: Given a list of intervals representing the start and end time of meetings, find all the intervals when a person is busy, considering that the person can attend only one meeting at a time.

Example: Intervals: [(1, 4), (2, 5), (7, 9)] Output: [(1, 5), (7, 9)] Explanation: The person is busy from 1 to 5 (attending meetings 1 and 2) and from 7 to 9 (attending meeting 3).

Solution:

def merge_intervals(intervals):
    if len(intervals) < 2:
        return intervals

    intervals.sort(key=lambda x: x[0])  # Sort intervals based on start time
    merged = []
    start, end = intervals[0]

    for i in range(1, len(intervals)):
        interval = intervals[i]
        if interval[0] <= end:  # Overlapping intervals
            end = max(end, interval[1])
        else:  # Non-overlapping interval found
            merged.append((start, end))
            start, end = interval

    merged.append((start, end))  # Add the last interval
    return merged

# Testing the function
intervals = [(1, 4), (2, 5), (7, 9)]
print(merge_intervals(intervals))