Square gauges: First qualifying slip
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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
roots. For each number x inreadings, find the largest whole number r whose square is at most x. A square means a number multiplied by itself. For example, x = 10 gives 3, because 3 * 3 = 9 but 4 * 4 = 16. Use whole-number comparisons, not rounded decimal square roots. Keep the answers in input order. - Read
rootsfrom left to right. Find the first number that is at leastkand store that number, not its position, infirstMatch. - Complete
squareGaugesFirstQualifyingSlipso it returnsfirstMatch. Return it, do not print it.
Example
If readings is [9, 8, 5, 7, 8] and k is 4, then roots is [3, 2, 2, 2, 2] and squareGaugesFirstQualifyingSlip returns -1.
Rules
- If no number is at least
k, return -1. 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 [0, 16, 3, 7, 16] and k is 4.
TEST DATA 2: readings is [8, 8, 8, 6] and k is 2.
Examples
Input: readings = [0,16,3,7,16] k = 4 Output: 4
roots is [0, 4, 1, 2, 4]. Here k is 4. The first number at least 4 is 4. Return that value.
Input: readings = [8,8,8,6] k = 2 Output: 2
roots is [2, 2, 2, 2]. Here k is 2. The first number at least 2 is 2. Return that value.
Input: readings = [] k = 1 Output: -1
roots is []. Here k is 1. No number is at least 1, 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 are whole numbers from 0 through 1000000.
Efficiency goal
Big-O describes how the work or memory needed grows as the input gets larger.
Efficiency goal: time O(n log M); extra memory, including the helper list, O(n). n is the input length; M is the largest input number. These labels describe how work and memory grow with the input.
Practice focus
Build roots 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.