Venkatesh-Prasad Ranganath rvprasad

Engineer + Researcher who is curious about software and computing.

rvprasad / bfsSolver2.groovy

Created April 15, 2018 22:50

Identifies a queue-based BFS traversal order of nodes of a given directed graph using z3 solver

	/*
	* Copyright (c) 2018, Venkatesh-Prasad Ranganath
	*
	* Licensed under BSD 3-clause License
	*
	* Author: Venkatesh-Prasad Ranganath
	*/

	import groovy.transform.Field

rvprasad / anonymizeNames.py

Last active May 5, 2018 20:41

Anonymizes the names (in names.txt) without disturbing the order and frequency of alphabet and number positions

	from random import randrange, sample, shuffle

	alphas = list('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
	nums = list('1234567890')
	shuffle(alphas)
	shuffle(nums)

	def scramble(s, seen):
	while True:
	ret = ''.join([(nums[int(x)] if x in nums else

rvprasad / extractCommentsWithPageNum.groovy

Last active May 24, 2023 01:30

Extracts comments associated with highlights in a PDF document along with page numbers

	/*
	* Copyright (c) 2018, Venkatesh-Prasad Ranganath
	*
	* Licensed under BSD 3-clause License
	*
	* Author: Venkatesh-Prasad Ranganath
	*
	* Adapted from https://stackoverflow.com/questions/33253757/java-apache-pdfbox-extract-highlighted-text
	*/

rvprasad / overlapping_intervals.py

Created November 6, 2018 03:50

Calculate the maximum number of overlapping intervals

	# Given a list of intervals, calculate the maximum number of overlapping intervals.
	# Each interval is inclusive at both ends.

	def solve(intervals): # list of pairs
	tmp1 = set(y for x in intervals for y in x)
	tmp2 = max(map(lambda x: sum(1 if y[0] <= x <= y[1] else 0 for y in intervals), tmp1))
	print "%s %d" % (intervals, tmp2)

	solve([(1,5), (2,4), (3, 6)])
	solve([(1,5), (2,3), (4, 6), (7,9)])

rvprasad / iperf-client-worst-case.yml

Last active February 5, 2019 00:02

Measure network throughput in worst case scenario -- many-to-one

rvprasad / iperf-client-best-case.yml

Last active February 5, 2019 00:01

Measure network throughput in best case scenario -- one-to-one

rvprasad / io-measure.cpp

Last active February 14, 2019 01:10

Measure throughput of default buffered I/O in different programming languages

	#include <chrono>
	#include <fstream>
	#include <iostream>
	using namespace std;

	int k = 256;
	int numOfNums = k * 1024 * 1024;
	int reps = 6;

	void writeUsingFile(string fileName) {

rvprasad / permutations.kt

Last active February 19, 2019 07:52

Permutation Generator (Algorithm from Cameron's "Combinatorics: Topics, Techniques, Algorithms")

	class PermutationGenerator(numOfValues:Int) : Iterator<List<Int>> {
	private val maxPos = numOfValues - 1
	private val values = (0..maxPos).shuffled()
	private var currPerm = (0..maxPos).toMutableList()

	@Synchronized override fun hasNext() = currPerm.isNotEmpty()

	@Synchronized override fun next(): List<Int> {
	val perm = currPerm.toList()
	val j = (maxPos - 1 downTo 0).find { currPerm[it] < currPerm[it + 1] }

rvprasad / parallelStreamAndAsSequence.kts

Last active February 21, 2019 05:02

Java parallel stream is significantly faster than the same stream converted into a Kotlin sequence

	import kotlin.streams.asSequence
	import kotlin.system.measureTimeMillis

	val k = 500000000L

	println(measureTimeMillis {
	java.util.stream.LongStream.range(1, k)
	.parallel()
	.asSequence()
	.map { it.toString().length.toLong() }

rvprasad / howManyLongsCanWeLoad.scala

Last active March 7, 2019 21:14

A script to identify how many longs can we store at a time with given heap size on JVM

	import scala.collection.mutable.ArrayBuffer
	import scala.util.Random

	object M {
	def main(args: Array[String]) {
	val t = new ArrayBuffer[Long]()
	while (true) {
	t += Random.nextLong
	if (t.length % 10000 == 0) {
	System.gc()