jyuv / mos-algorithm

Python implementation of Mo's Algorithm - a method for answering a series of range queries on the same array. The repository provides a general interface for Mos operations

Mos-Algorithm

Overview

Python implementation of Mo's Algorithm - a method for answering a series of range queries on the same array.

Running time and space complexity of this method are:

The repository provides a general interface for Mos operations to later be adjusted to specific tasks, and 2 examples of such tasks.

Use Case Example 1 - Sum In Range

Given an array this example answers efficiently a series of range queries where each query calculate the sum of its range.

from mos_algorithm import MosAlgorithm, SumInRange
input_array = [1, 1, 2, 1, 3, 4, 5, 2, 8]
queries = [(0, 4), (1, 3), (2, 4)]
case1 = MosAlgorithm(input_array, queries)
case1.run_queries(SumInRange)

Use Case Example 2 - Unique Items In Range

Given an array this example answers efficiently a series of range queries where each query calculate the number of unique items in its range.

from mos_algorithm import MosAlgorithm, UniqueItemsInRange
input_array = [1, 1, 2, 1, 3, 4, 5, 2, 8]
queries = [(0, 4), (1, 3), (2, 4)]
case1 = MosAlgorithm(input_array, queries)
case1.run_queries(UniqueItemsInRange)