Top-K Accuracy

MediumMachine LearningMathArrayMatrix

Description

Given a 2D array of class scores (one row of scores per sample), an array of true class indices, and an integer k, return the top-k accuracy: the fraction of samples whose true class is among the k highest-scoring classes. Break score ties toward the lower index. Round the result to 4 decimal places.

Examples

Input:[[1,3,2],[5,1,0]], [1,0], 2
Output:1
Explanation:

A sample counts as correct when its true class appears anywhere among the k highest-scoring predictions, and the correct fraction is reported.

Input:[[1,2,3],[3,2,1]], [0,0], 1
Output:0.5
Explanation:

A sample counts as correct when its true class appears anywhere among the k highest-scoring predictions, and the correct fraction is reported.

Input:[[5,1],[1,5]], [0,1], 1
Output:1
Explanation:

A sample counts as correct when its true class appears anywhere among the k highest-scoring predictions, and the correct fraction is reported.

Constraints

  • 1 ≤ samples ≤ 10³
  • 1 ≤ k ≤ number of classes

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