Fixed panels: First qualifying slip
Stuck or curious how this works? Visualize Two Pointers ↗
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
windowSums. A window is a group of numbers next to each other. Take each window of exactlyknumbers inreadings, moving one place right each time. Record each window sum from left to right. If the whole input has fewer thanknumbers,windowSumsis empty. - Read
windowSumsfrom left to right. Find the first number that is at leastkand store that number, not its position, infirstMatch. - Complete
fixedPanelsFirstQualifyingSlipso it returnsfirstMatch. Return it, do not print it.
Example
If readings is [5, 8, 3, 8, -9] and k is 4, then windowSums is [24, 10] and fixedPanelsFirstQualifyingSlip returns 24.
Rules
- If no number is at least
k, return -1. k(a whole number from 1 to 8) is the window size in task 1, and also the threshold in task 2.
Test data
TEST DATA 1: readings is [0, 12, 12, -10, 4] and k is 3.
TEST DATA 2: readings is [-9, 3, 3, 3] and k is 7.
Examples
Input: readings = [0,12,12,-10,4] k = 3 Output: 24
windowSums is [24, 14, 6]. Here k is 3. The first number at least 3 is 24. Return that value.
Input: readings = [-9,3,3,3] k = 7 Output: -1
windowSums is []. Here k is 7. No number is at least 7, so return -1.
Input: readings = [] k = 6 Output: -1
windowSums is []. Here k is 6. No number is at least 6, so return -1.
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 windowSums 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.