Search a sorted array
Given a strictly increasing array and a target, return its zero-based index or -1 when absent. Inputs are valid JSON and must not be modified unless the algorithm uses a local copy. This exercise probes typed data modeling, boundary handling, and algorithm selection.
Input
One JSON value: { values: number[]; target: number }. See the sample for its exact shape.
Output
One compact JSON value of type number. Strings include JSON quotes; arrays preserve the specified order.
Constraints
Array/string lengths are 0 to 10000 unless stated otherwise. Numbers are integers in [-1000000,1000000]; all computed results fit the safe integer range.
Example
Input
{"values":[1,3,5,9],"target":5}Output
2
Example 2 input
{"values":[1,2,3,4],"target":4}Output
3
Checks a boundary or contrasting case beyond the public examples.
Public test cases (2)
Input
{"values":[1,3,5,9],"target":5}Expected output
2
Input
{"values":[],"target":1}Expected output
-1
Hints (2)
- Start with the required output order and the empty-input behavior.
- Halve the remaining search interval
Target complexity: time O(log(n+1)) · space O(1)