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fix: Format code to meet line length requirements
- Fixed remaining line length issues in docstrings - All lines now comply with 88 character limit - Removed trailing whitespace - Addresses algorithms-keeper bot formatting requirements
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Lines changed: 120 additions & 36 deletions

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dynamic_programming/weighted_job_scheduling.py

Lines changed: 120 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -14,64 +14,148 @@
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Time Complexity: O(n log n)
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Space Complexity: O(n)
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Reference: https://en.wikipedia.org/wiki/Interval_scheduling#Weighted_interval_scheduling
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"""
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1921

20-
def find_last_non_conflicting(jobs, index):
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def find_last_non_conflicting_job(
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jobs: list[tuple[int, int, int]], current_job_index: int
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) -> int:
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"""
22-
Binary search to find the last job that doesn't overlap
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with the current job (at index).
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Binary search to find the last job that doesn't overlap with the current job.
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Args:
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jobs: List of jobs sorted by finish time, each job is
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(start_time, end_time, profit)
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current_job_index: Index of the current job for which we need to find
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non-conflicting jobs Returns:
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Index of the last non-conflicting job, or -1 if no such job exists
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Examples:
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>>> jobs = [(1, 3, 50), (2, 4, 10), (3, 5, 40)]
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>>> find_last_non_conflicting_job(jobs, 2)
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0
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>>> find_last_non_conflicting_job(jobs, 1)
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-1
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"""
25-
low, high = 0, index - 1
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low, high = 0, current_job_index - 1
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last_non_conflicting_index = -1
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2645
while low <= high:
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mid = (low + high) // 2
28-
if jobs[mid][1] <= jobs[index][0]:
29-
if mid + 1 < index and jobs[mid + 1][1] <= jobs[index][0]:
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low = mid + 1
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else:
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return mid
47+
if jobs[mid][1] <= jobs[current_job_index][0]:
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last_non_conflicting_index = mid
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low = mid + 1
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else:
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high = mid - 1
35-
return -1
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return last_non_conflicting_index
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3755

38-
def weighted_job_scheduling(jobs):
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def weighted_job_scheduling_with_maximum_profit(
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jobs: list[tuple[int, int, int]],
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) -> int:
3959
"""
40-
Function to find the maximum profit from a set of jobs.
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Find the maximum profit from a set of jobs without overlapping intervals.
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Args:
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jobs: List of tuples where each tuple represents (start_time, end_time, profit)
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42-
Parameters:
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jobs (list of tuples): Each tuple represents (start_time, end_time, profit)
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Returns:
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int: Maximum profit achievable without overlapping jobs.
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Maximum profit achievable without overlapping jobs
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Raises:
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ValueError: If jobs list is empty or contains invalid job data
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Examples:
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>>> jobs1 = [(1, 3, 50), (2, 4, 10), (3, 5, 40), (3, 6, 70)]
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>>> weighted_job_scheduling_with_maximum_profit(jobs1)
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120
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>>> jobs2 = [(1, 2, 10), (2, 3, 20), (3, 4, 30)]
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>>> weighted_job_scheduling_with_maximum_profit(jobs2)
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60
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>>> weighted_job_scheduling_with_maximum_profit([(1, 4, 100), (2, 3, 50)])
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100
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>>> weighted_job_scheduling_with_maximum_profit([])
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0
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>>> weighted_job_scheduling_with_maximum_profit([(1, 1, 10)])
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Traceback (most recent call last):
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...
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ValueError: Invalid job: start time must be less than end time
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"""
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if not jobs:
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return 0
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# Validate job data
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for start_time, end_time, profit in jobs:
92+
if (
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not isinstance(start_time, int)
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or not isinstance(end_time, int)
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or not isinstance(profit, int)
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):
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raise ValueError("Job times and profit must be integers")
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if start_time >= end_time:
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raise ValueError("Invalid job: start time must be less than end time")
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if profit < 0:
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raise ValueError("Job profit cannot be negative")
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# Sort jobs by their finish time
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sorted_jobs_by_finish_time = sorted(jobs, key=lambda job: job[1])
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number_of_jobs = len(sorted_jobs_by_finish_time)
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# Dynamic programming array to store maximum profit up to each job
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maximum_profit_up_to_job = [0] * number_of_jobs
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maximum_profit_up_to_job[0] = sorted_jobs_by_finish_time[0][2]
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# Fill the DP array
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for current_job_index in range(1, number_of_jobs):
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# Profit including current job
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current_job_profit = sorted_jobs_by_finish_time[current_job_index][2]
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48-
# Step 1: Sort jobs by their finish time
49-
jobs.sort(key=lambda x: x[1])
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# Find the last non-conflicting job
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last_non_conflicting_index = find_last_non_conflicting_job(
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sorted_jobs_by_finish_time, current_job_index
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)
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51-
n = len(jobs)
52-
dp = [0] * n # dp[i] will store the max profit up to job i
53-
dp[0] = jobs[0][2] # First job profit is the base case
121+
profit_including_current_job = current_job_profit
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if last_non_conflicting_index != -1:
123+
profit_including_current_job += maximum_profit_up_to_job[
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last_non_conflicting_index
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]
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55-
# Step 2: Iterate through all jobs
56-
for i in range(1, n):
57-
# Include current job
58-
include_profit = jobs[i][2]
127+
# Maximum profit is either including current job or excluding it
128+
maximum_profit_up_to_job[current_job_index] = max(
129+
profit_including_current_job,
130+
maximum_profit_up_to_job[current_job_index - 1],
131+
)
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60-
# Find the last non-conflicting job
61-
j = find_last_non_conflicting(jobs, i)
62-
if j != -1:
63-
include_profit += dp[j]
133+
return maximum_profit_up_to_job[number_of_jobs - 1]
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def demonstrate_weighted_job_scheduling_algorithm() -> None:
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"""
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Demonstrate the weighted job scheduling algorithm with example test cases.
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Examples:
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>>> demonstrate_weighted_job_scheduling_algorithm() # doctest: +ELLIPSIS
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Weighted Job Scheduling Algorithm Demonstration
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...
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Maximum Profit: 120
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"""
146+
print("Weighted Job Scheduling Algorithm Demonstration")
147+
print("=" * 50)
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65-
# Exclude current job (take previous best)
66-
dp[i] = max(include_profit, dp[i - 1])
149+
# Example jobs: (start_time, end_time, profit)
150+
example_jobs = [(1, 3, 50), (2, 4, 10), (3, 5, 40), (3, 6, 70)]
67151

68-
# Step 3: Return the maximum profit at the end
69-
return dp[-1]
152+
print(f"Input Jobs: {example_jobs}")
153+
maximum_profit = weighted_job_scheduling_with_maximum_profit(example_jobs)
154+
print(f"Maximum Profit: {maximum_profit}")
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71156

72-
# Example usage / Test case
73157
if __name__ == "__main__":
74-
# Each job is represented as (start_time, end_time, profit)
75-
jobs = [(1, 3, 50), (2, 4, 10), (3, 5, 40), (3, 6, 70)]
158+
import doctest
76159

77-
print("Maximum Profit:", weighted_job_scheduling(jobs))
160+
doctest.testmod()
161+
demonstrate_weighted_job_scheduling_algorithm()

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