Author Archives: jeffrin

Project Euler Problem 2, solution internals related using ruby debugger

$ruby -rdebug euler-two.rb Debug.rb Emacs support available. /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) r /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) r /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) next /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:143: RUBYGEMS_ACTIVATION_MONITOR.exit (rdb:1) next euler-two.rb:3:n1, n2 = 1, 2 (rdb:1) next euler-two.rb:4:sum = 0 (rdb:1) print n1 1nil (rdb:1) print n2 2nil (rdb:1) next euler-two.rb:6:while n2 < 4000000 (rdb:1) print n2 2nil (rdb:1) next euler-two.rb:7:sum += …

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Project Euler Problem 3, solution internals using python debugger

$python -m pdb euler-three.py > /home/jeffrin/beautifulwork/lib/euler-three.py(7)() -> ”’ (Pdb) r 6857 –Return– > /home/jeffrin/beautifulwork/lib/euler-three.py(17)()->None -> print n (Pdb) next –Return– > (1)()->None (Pdb) next The program finished and will be restarted > /home/jeffrin/beautifulwork/lib/euler-three.py(7)() -> ”’ (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(9)() -> n = 600851475143 (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(11)() -> i = 2 (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(12)() …

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Project Euler Problem 2, solution internals using python debugger

$python -m pdb project-euler-2.py > /home/jeffrin/beautifulwork/lib/project-euler-2.py(13)() -> ”’ (Pdb) next > /home/jeffrin/beautifulwork/lib/project-euler-2.py(15)() -> cache = {} (Pdb) next > /home/jeffrin/beautifulwork/lib/project-euler-2.py(16)() -> def fib(n): (Pdb) next > /home/jeffrin/beautifulwork/lib/project-euler-2.py(20)() -> n = 0 (Pdb) next > /home/jeffrin/beautifulwork/lib/project-euler-2.py(21)() -> i = 0 (Pdb) next > /home/jeffrin/beautifulwork/lib/project-euler-2.py(22)() -> while fib(i) /home/jeffrin/beautifulwork/lib/project-euler-2.py(23)() -> if not fib(i) % 2: n = …

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How to write an algorithm to find among natural numbers the sum of multiples of 3 and 5 below 1000 ?

/* This program has been worked on from http://www.s-anand.net/euler.html */ #include <stdio.h> sofmul() { int n, i; n = 0; for (i = 0 ; i < 1000 ; i++) { if ( !(i % 5) || !(i % 3) ) n = n + i; } printf(“Sum of the multiples of 3 and 5 …

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GDB backtrace For chromium hangup

(gdb) bt #0 pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:238 #1 0x00007fb512be9443 in ?? () #2 0x00007fb512bc9d0d in ?? () #3 0x00007fb512bacb0f in ?? () #4 0x00007fb512bbc7d1 in ?? () #5 0x00007fb512baa03a in ?? () #6 0x00007fb51537aea8 in ?? () #7 0x00007fb512b7d045 in ?? () #8 0x00007fb512b7de1e in ?? () #9 0x00007fb512b7cc30 in ?? () #10 0x00007fb512569698 in …

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How to write a program to multiply a number by 4 using a bitwise operator ?

/* Part of this program copied from http://www.sanfoundry.com/c-program-multiply-number-4-using-bitwise-operators/ */ #include <stdio.h> multbitwise() { long number; printf(“Enter an integer: “); scanf(“%ld”,&number); number = number << 2; printf(“Result is %ld \n”,number); } /* http://stackoverflow.com/questions/4456442/interview-multiplication-of-2-integers-using-bitwise-operators */ /* http://www.geeksforgeeks.org/multiply-two-numbers-without-using-multiply-division-bitwise-operators-and-no-loops/ */ /* http://en.wikipedia.org/wiki/Bitwise_operation */

Hacking with conversions of decimal and binary

$./app Sign detection [1] Power of two [2] Counting No. of bits set [3] Set or clear bits without branching[4] Find maximum value[5] Finding least common multiple[6] Finding the greatest commom divisor[7] Finding if a number is an Armstrong number or not[8] Finding if a given number is prime number[9] Finding the number of twin …

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How to write an algorithm to reverse an integer ?

/* Part of this work is copied from http://www.sanfoundry.com/c-program-to-reverse-a-given-number/ */ #include <stdio.h> revint() { long num, reverse = 0, temp, remainder; printf(“Enter the number \n”); scanf(“%ld”,&num); temp = num; while ( num > 0 ) { remainder = num % 10; reverse = reverse * 10 + remainder; num /= 10; } printf(“Given number = …

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Hacking with an algorithm to reverse an integer

$./app Sign detection [1] Power of two [2] Counting No. of bits set [3] Set or clear bits without branching[4] Find maximum value[5] Finding least common multiple[6] Finding the greatest commom divisor[7] Finding if a number is an Armstrong number or not[8] Finding if a given number is prime number[9] Finding the number of twin …

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