Neighbor notes: Threshold file
Inputs
readings is a list of integers (numbers with no decimal part). It may be empty, and numbers may repeat unless task 1 says otherwise.
Your tasks
- Create a list
differences. Start at the second number inreadings. Subtract the number just before it from the current number. Repeat for each later number. Put the answers in order. For [5, 8, 2],differencesis [3, -6]. A list with fewer than two numbers gives an emptydifferences. - Count the numbers in
differencesthat are at leastk(greater than or equal tok). Store the count inatLeastK. - Complete
neighborNotesThresholdFileso it returnsatLeastK. Return it, do not print it.
Example
If readings is [-5, 4, 5, 5, 2] and k is 4, then differences is [9, 1, 0, -3] and neighborNotesThresholdFile returns 1.
Rules
- If
differencesis empty, the count is 0. k(a whole number from 1 to 8) is the threshold in task 2: compare each number with it.
Test data
TEST DATA 1: readings is [3, 10, 0, 10, -4] and k is 4.
TEST DATA 2: readings is [3, -3, 3, 3] and k is 7.
Examples
Input: readings = [3,10,0,10,-4] k = 4 Output: 2
differences is [7, -10, 10, -14]. Here k is 4. The numbers at least 4 are [7, 10]. There are 2, so return 2.
Input: readings = [3,-3,3,3] k = 7 Output: 0
differences is [-6, 6, 0]. Here k is 7. The numbers at least 7 are []. There are 0, so return 0.
Input: readings = [] k = 1 Output: 0
differences is []. Here k is 1. The numbers at least 1 are []. There are 0, so return 0.
Input limits
- 0 <= input size <= 64.
- k is a whole number from 1 to 8. Answers fit in a signed 32-bit integer: -2,147,483,648 through 2,147,483,647.
- Input numbers have no decimal part. They range from -1,000,000 to 1,000,000. Follow any extra input rules in task 1.
Efficiency goal
Big-O describes how the work or memory needed grows as the input gets larger.
Efficiency goal: time O(n); extra memory, including the helper list, O(n). n is the input length. These labels describe how work and memory grow with the input.
Practice focus
Build differences first, then return exactly what the tasks ask for. Follow the order, keep repeated values when the rule says so, and check the empty case.