Programming Job Skills Test?

eclecticgeek asks: "I've recently finished a CS/SD degree at uni and the interviews are starting to come thick and fast. I've yet to have a skills test for any of them, and it's only a matter of time before I do. I'm hoping to do one this week and I will get the choice of language. The position is quite broad and they're more after competent programmers in general, rather than any one specific language. So I'm wondering, have you done a developer skills test? What type of things did you get asked?"

Comments

Don't fret over this

[marcus]

Sometimes it is not the code that counts, but your approach. Are you applying for a software "design" position? If so, then show some evidence of designing something before you code. Consider the position you are targeting. Application software? Embedded firmware with restricted resources? Is pure speed important? Code size? Maintainability? Portability? Ask for a more detailed spec if what is given is too vague, or just put comments in your code showing where things should/could be changed if your interpretation of the spec is wrong.

If you are competent, you'll be OK. Every coding position I've ever had included a skills test, except one. The one exception was for a position at a company that I had already worked for in the past...

General Logic

[web_boyo_in_sac]

I got this at my last job as part of my second interview, thankfully it was a take home "quiz".

"You are stranded on a deserted island, thousands of miles from nowhere you are forced to survive with what you have.

You have a handful of nails, a hatchet with a hammer head, 100 feet of rope, a large lens and a few dozen square yards of sail cloth.

The island has a variety of birdlife, fishing and crabs, but mostly inedible seeds, very acidic but edible berries and a large grove of coconut palms.

One side of the island seems to be geothermally active with several hot springs and some sulfer smelling vents, and a large variety of volcanic rock, obsidian and flint along with some hematite and copper deposits.

Now given this very restricted and scientifically unplausible situation, how would you survive?
Please take as much time as you need and give as thorough an answer as possible."

Re:General Logic

[GlenRaphael]

I'll take a brief stab at it.

Immediately, you need water, food and shelter. Shelter is the easiest: tie a length of rope between two palm trees, drape the sail cloth over the line and weigh down the corners appropriately; you've got a basic pup tent or tube tent to (somewhat) protect yourself from the sun and the wind.

You can get water from coconuts a la Cast Away. Use the obsidian to fashion spear heads for fishing, and the flint to sharpen your axe. (You can actually catch fish in a river with your hands alone - I'm not sure if that applies here. In any case, tools are a good thing. ) Crabs should be pretty easy to catch with the help of a cup or a basket or a spear.

Use the "large lens" to start a fire for warmth at night and to cook the fish. And perhaps to look for ships.

Medium term: Build a big SOS sign and have moss handy to throw on the fire for smoke to signal any passing plane or boat. Build a more permanent shelter. Explore the entire island and inventory everything on it.

Long term: Build a smokehouse. Find ways to accumulate and stockpile excess water and food and firewood beyond your daily needs -- especially water. If no rescue boat shows up, ultimately build a raft or sailboat and take your chances.

Eat the berries every once in a while so you don't get scurvy. I don't know enough metalurgy to do anything with the sulfer/hematite/copper, but it's not clear you need it anyway. Do you? What am I missing? If I knew metalurgy I'd probably want to cast more nails or make a drill bit...

Re:General Logic

[bladesjester]

Actually, copper's even easier than that. Copper is one of the few metals that can be worked in a fire as cold as a campfire (this is where I put on my smith's hat).

In order to extract the copper, all you really need to do is break the rocks up into smallish pieces and toss them in the fire. when the fire has gone out, remove the rocks, and dig the copper out of the sand. To work it, just build another fire to heat it.

You don't want to hammer it cold. It cracks like you wouldn't believe.

To extract the iron from the hematite, you'd basically need to make a crude bloom forge or a primitive smelter. The palm fronds would provide the carbon content if you could get the fire hot enough (The Japanese used rice stalks and charcoal to smelt the black sand that was used in the production of swords before they started trading for higher grade materials that were easier to work with). The main difficulty in getting the fire hot enough is forcing air through the fire, so it's really not all *that* difficult.

As far as the iron being too hard to work with a rock, it's not. The master I studied with did an amusing trick by making horse shoes using a glass coke bottle for a hammer. To make a basic hammer, all you need is to take a piece of steel (which you can make and mold, or even shape with the hammer head of the axe) that is rectangular and affix a handle to it.

Re:Can't prepare

[Smallpond]

"one place that set me down with a bug report and a development box with their code on it and wanted to see how I'd approach it..."

That wasn't a real interview. They just couldn't find that one nasty code bug so they brought people in until someone found it.

Gilligan's Island

[obtuse]

First - survival, but you might have one volatile asset to help with your rescue. Do you have a watch, and is it still running and on time? Do you know the date? If so, the sooner you take a reading of the angle of the sun & combine it with the time, the more accurately your position can be determined. Otherwise, start tracking the arc of a shadow & wait for the solstice, & take a readings then. Include these readings on the messages you toss into the sea. (Pumice, coconut husks?)

Make shoes - you won't live long if your feet give out. Any injury could kill you by way of infection. Make clothes from the cloth, and conserve it. It will deteriorate in the sun, but better it than your skin. If you can clothe yourself with feathers or anything else, you want to do that instead. Depending on how long you are on the island, you may need to make a sail from the cloth. It is also a source of fine thread. You might use it to skin a boat.

Make a prominent distress sign, visible from the air.

You can distill water from the hydrothermal vents, or at least use the heat to distill seawater.

Can you make a compass from the hematite or nails? If the hematite is specular hematite, it may be possible to polish it into a signalling mirror. Try the copper too.

With the copper & nails as a battery (voltaic pile) you could make a spark gap generator to produce radio noise. It's a little Gilligan's Island, but you could probably rig a machine (powered by wind, or gravity by way of ported water or sand) to use this to constantly transmit SOS. Depending on your ability to work the copper, you may be able to make enough wire to make a simple radio receiver & speaker. You may need to use your battery to magnetize pieces of nails.

If the wind is constant enough, you might make a kite to hoist an antenna.

Can the seeds be made edible after making into flour and treating with ashes or the acid from the berries? Acorns aren't edible either, but lot's of people have survived on them. Vary your diet to avoid scurvy, ricketts or worse.

How large is the lens? If it's a page sized fresnel lens, then you can melt concrete with those, so smelting small quantities of iron is not entirely implausible. A blind spot in the center of your vision won't improve your survival odds, so don't look at the hot spot. Hang the lens on a frame.

Prepare a signal fire, & keep coals ready to light it. Don't burn down your coconut trees.

Can the berries be fermented? Not just for entertainment, but alcohol can clean wounds, and could be useful for fuel.

Nothing gets thrown away or tossed into the sea. Make a latrine in a place that won't cause any trouble. Even your waste is a resource. Look out for birdlime. You might just be able to make a black powder flare for signalling from that, the sulfur & some charcoal. Burn as little as you must, as you don't have time to wait for fuel to grow. Besides, you've got free heat from the hydrothermal vents.

As others have said: Obsidian & flint: Knives, spear points. Coppper -fishhooks. You could probably work the nails too. Lots of other excellent suggestions here. With the copper & hematite, you should be able to make a diode, and from that a radio receiver. Good luck making a speaker or earphone. Homemade wire, nail fixed magnet, diaphragm of palm or cloth. Handy, but probably impossible: Triode amplifier.

Finally, use wax from the berries & feathers from the birds, & make wings. Fly away, but don't get too close to the sun, or the wax will melt and you'll fall into the sea, to the dismay of your father.

A related problem is how does one make accurate tools or measuring devices without already having them? One way to start is by making a flat surface by rubbing two things together.