microsoft/qdk
Publicmirrored fromhttps://github.com/microsoft/qdkAvailable
samples/algorithms/HypercubeLookup/src/ClassicalSearch.qs
39lines · modecode
| 1 | import Std.Diagnostics.*; |
| 2 | import Std.Arrays.*; |
| 3 | |
| 4 | /// # Summary |
| 5 | /// Classically finds the index of a vertex in the list of vertices |
| 6 | /// whose distance to the query vertex is below the given threshold. |
| 7 | function GetIndexBelowThresholdClassically( |
| 8 | vertices : Bool[][], |
| 9 | query : Bool[], |
| 10 | threshold : Int |
| 11 | ) : Int { |
| 12 | Fact(not IsEmpty(vertices), "Vertex list must not be empty."); |
| 13 | mutable foundIndex = -1; |
| 14 | for idx in IndexRange(vertices) { |
| 15 | let vertex = vertices[idx]; |
| 16 | let distance = HammingDistance(vertex, query); |
| 17 | if distance < threshold { |
| 18 | Fact(foundIndex == -1, "More than one vertex found below the threshold."); |
| 19 | set foundIndex = idx; |
| 20 | } |
| 21 | } |
| 22 | Fact(foundIndex != -1, "No vertex found below the threshold."); |
| 23 | return foundIndex; |
| 24 | } |
| 25 | |
| 26 | /// # Summary |
| 27 | /// Computes the Hamming distance between two bit strings. |
| 28 | /// This serves as a multidimensional Manhattan distance (L₁ distance) |
| 29 | /// for vertex coordinates represented as bit strings. |
| 30 | function HammingDistance(a : Bool[], b : Bool[]) : Int { |
| 31 | Fact(Length(a) == Length(b), "Arrays must be of the same length."); |
| 32 | mutable distance = 0; |
| 33 | for i in IndexRange(a) { |
| 34 | if a[i] != b[i] { |
| 35 | distance += 1; |
| 36 | } |
| 37 | } |
| 38 | return distance; |
| 39 | } |
| 40 | |