Program to find total duration of K most watched shows in Python

Suppose we have a list of strings called shows, a list of integers called durations, and a value k. Here shows[i] and durations[i] represent a show and its duration watched by the ith person. We need to find the total duration watched of the k most watched shows.

So, if the input is like shows = ["The BGT", "Jack jumper", "The BGT", "Jokers Company", "Music magic"] durations = [10, 8, 10, 18, 9] k = 2, then the output will be 38, as the top 2 most watched shows are "Jokers Company" and "The BGT" with total durations of 18 and (10 + 10) = 20, giving us 18 + 20 = 38.

Algorithm

To solve this, we will follow these steps ?

• If shows is empty or durations is empty or k is 0, then return 0

• Create a dictionary to store total duration for each show

• For each show and duration pair, add the duration to the show's total

• Extract all duration values and sort them in descending order

• Sum the top k durations and return the result

Example

Let us see the following implementation to get better understanding ?

from collections import defaultdict

def solve(shows, durations, k):
    if not shows or not durations or not k:
        return 0
    
    # Dictionary to store total duration for each show
    show_durations = defaultdict(int)
    
    # Calculate total duration for each show
    for i in range(len(shows)):
        show_durations[shows[i]] += durations[i]
    
    # Get all durations and sort in descending order
    all_durations = list(show_durations.values())
    all_durations.sort(reverse=True)
    
    # Sum the top k durations
    total = 0
    for i in range(min(k, len(all_durations))):
        total += all_durations[i]
    
    return total

# Test the function
shows = ["The BGT", "Jack jumper", "The BGT", "Jokers Company", "Music magic"]
durations = [10, 8, 10, 18, 9]
k = 2

result = solve(shows, durations, k)
print(f"Total duration of top {k} shows: {result}")

The output of the above code is ?

Total duration of top 2 shows: 38

How It Works

The algorithm works by first aggregating the total watch time for each show using a dictionary. For our example:

• "The BGT": 10 + 10 = 20

• "Jack jumper": 8

• "Jokers Company": 18

• "Music magic": 9

Then we sort these totals in descending order [20, 18, 9, 8] and sum the top k=2 values: 20 + 18 = 38.

Alternative Approach Using heapq

For better performance with large datasets, we can use Python's heapq module ?

import heapq
from collections import defaultdict

def solve_optimized(shows, durations, k):
    if not shows or not durations or not k:
        return 0
    
    # Calculate total duration for each show
    show_durations = defaultdict(int)
    for show, duration in zip(shows, durations):
        show_durations[show] += duration
    
    # Get top k durations using heap
    top_k_durations = heapq.nlargest(k, show_durations.values())
    
    return sum(top_k_durations)

# Test the optimized function
shows = ["The BGT", "Jack jumper", "The BGT", "Jokers Company", "Music magic"]
durations = [10, 8, 10, 18, 9]
k = 2

result = solve_optimized(shows, durations, k)
print(f"Total duration (optimized): {result}")

The output of the above code is ?

Total duration (optimized): 38

Conclusion

The problem is solved by aggregating show durations in a dictionary, then finding the sum of the k largest values. The heapq.nlargest() approach is more efficient for large datasets as it avoids sorting the entire list.