Algorithm for Identifying Largest Differences in Sorted Number Lists

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Solution Overview

Problem

Conventional methods for finding the k largest difference values from a set of n arbitrary numbers are inefficient, requiring O(n^2) time complexity due to exhaustive search and high memory usage, especially in applications like clock-skew analysis in digital IC design.

Innovation Solution

The method sorts the input set of numbers and utilizes properties of sorted lists to reduce the search space to k(k+1)/2 difference values, allowing for efficient identification of the k largest differences with a time complexity of O(n log n) for sorting and O(k^2 log k) for partial sorting, independent of the input list size n.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If exhaustive search method is used to find all possible differences, then completeness of difference identification is improved, but time complexity increases to O(n^2)

Engineering Contradiction:
Improvecompleteness of difference identificationVSAvoidtime complexity
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the necessary differences (largest k differences) rather than computing all possible differences. By using sorting to identify the k largest differences directly from the sorted array, the method extracts only the needed information, reducing the solution space from O(n^2) to O(k log n) time complexity while maintaining completeness for the top k differences.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary sorting of the input array in O(n log n) time before extracting differences. This preliminary action organizes the data in a way that enables efficient extraction of the k largest differences without needing to check all possible pairs, thus reducing overall time complexity while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If exhaustive search method is used to compute all difference values, then accuracy of difference identification is improved, but memory usage increases

Engineering Contradiction:
Improveaccuracy of difference identificationVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the k largest differences rather than storing all possible differences. By maintaining only the top k differences in memory during the extraction process, the method significantly reduces memory requirements from O(n^2) to O(k) while preserving accuracy for identifying the largest differences.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by computing and storing only the necessary k largest differences rather than all possible differences. This partial extraction approach reduces memory usage while maintaining sufficient accuracy for the application, avoiding the excessive memory consumption of storing the complete difference matrix.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of time

If conventional sorting algorithm is used to sort input numbers, then time complexity is reduced to O(n log n), but the solution space reduction to k(k+1)/2 differences is achieved

Engineering Contradiction:
Improvetime complexityVSAvoidsolution space structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent performs preliminary sorting of the input array in O(n log n) time, which organizes the data to enable efficient extraction of the k largest differences. This preliminary sorting action, combined with the mathematical property that the largest differences must involve the largest and smallest elements, reduces the solution space to k(k+1)/2 potential candidates, achieving both time efficiency and solution space reduction.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS7653673B1Efficient method for identifying few largest differences from a list of numbers
Publication Date: 2010.01.26 NAT SEMICON CORP
  • US7653673B1 patent drawing
  • US7653673B1 patent drawing
  • US7653673B1 patent drawing

AI summary

A method is provided that finds the largest 'k' difference values in decreasing order from a list of 'n' arbitrary numbers. The method uses the property of sorted numbers to organize the list of all the differences in a way that reduces the size of the solution space. The time complexity of the solution space using the method is O(k2), as compared to O(n2) in the conventional exhaustive method. The overall time complexity of the method is bound by the complexity of the algorithm used to sort the input list of numbers. The memory complexity of the method is less than the exhaustive method when k<<n.