If you were out walking and came across a magic relic that could give you very accurate weather for the next 30 days in a location, how would you productize it for Google?
- Relic has to be in the location to get the weather, gets weather for 30 days in a 30 mile radius of it's location.
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This answer builds over the previous answer to prove building such a drone is possible.
Given the radius of earth ~4k miles, and the area covered by the relic 30miles, the number of observation points over earth that it needs to visit to cover the entire surface area are:
4*pi*(4k)^2/pi*30^2 ~= 70k
of these 70% points fall over oceans, and another 10% over uninhabited areas. leaving the observation points of interest as only 20% of 70k = 14k
Assuming a shortest path algorithm can be written to direct the drone to hop 30miles at a time to get to the next observation point, and the large masses of ocean and uninhabited areas can be completely avoided, the total distance travelled by such drone is 14k*30miles, which needs to be traveresed within 30 days. So the speed needed is:
14k*30miles/30days ~= 500MPH. This is a speed of a standard aircraft, and is quite feasible for a drone.
Also, there is a total of 70k*1ms = 70sec time taken for the relic to actually make all observations, which is negligible for the above computation.
Given the radius of earth ~4k miles, and the area covered by the relic 30miles, the number of observation points over earth that it needs to visit to cover the entire surface area are:
4*pi*(4k)^2/pi*30^2 ~= 70k
of these 70% points fall over oceans, and another 10% over uninhabited areas. leaving the observation points of interest as only 20% of 70k = 14k
Assuming a shortest path algorithm can be written to direct the drone to hop 30miles at a time to get to the next observation point, and the large masses of ocean and uninhabited areas can be completely avoided, the total distance travelled by such drone is 14k*30miles, which needs to be traveresed within 30 days. So the speed needed is:
14k*30miles/30days ~= 500MPH. This is a speed of a standard aircraft, and is quite feasible for a drone.
Also, there is a total of 70k*1ms = 70sec time taken for the relic to actually make all observations, which is negligible for the above computation.
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Q: Can I clone it?
A: No
Q: Can I break it into 1000 pieces and will it still work?
A: No
----
candidate: Okay so basically take it and run around the earth :) Lol.
Okay so let me ask another question, can I assume that only 50% of the world is using the google weathers app?
Interviewer: no assume that the entire world is using.
---
Candidate: Can I assume that it will work 100 feet high from earth?
interviewer: yes
Candidate how about 2 km -5 km high?
interviewer: yes
---
Candidate: What's the response time to tell the weather, can I assume it's extremely fast like 1ms or even lesser
interviewer: okay assume.
---
candidate: Can I assume that I can have an extremely high-speed drone, that says has the permissions from all government to fly over their country, each country can ask it to land anytime and inspect.
interviewer: okay let's assume that
---
candidate: I will make this drone that will carry this and fly over all countries and cities but needs to complete that circle in 30 days.
Interviewer: the world has this many countries and these many cities, overall world area is too huge, do you think it can complete all of it and come back in 30 days?
Candidate: it now becomes and maths and traversal problem. there are two ways to proceed.
in one operation we are able to cover 2*pi*30 miles, now calculate the entire earth's surface area.
how many scans will be needed?
I don't know how that numbers will be but it comes out to say less than 30(days)*24(hours)*60(seconds) then we cant use it for the entire earth.
then we will have to prioritize based on the usage.
If you think we cant travel faster, I will ask if we can this magic relic even higher up in the space and if it will still work? When gravity is less we can traverse even faster. I can have a satellite that travels super fast and takes all this data.
Also, I did not ask at the beginning when it takes 1 km or 5 km up from the ground, does the coverage increases? if yes then that reduces the size of the problem.
Just want to if you are looking for imagination or structure of thinking or exact maths number, I am assuming the combination of the first two.
Let me know if you want me to go into detail about maths.
Interviewer: I think that's okay
A: No
Q: Can I break it into 1000 pieces and will it still work?
A: No
----
candidate: Okay so basically take it and run around the earth :) Lol.
Okay so let me ask another question, can I assume that only 50% of the world is using the google weathers app?
Interviewer: no assume that the entire world is using.
---
Candidate: Can I assume that it will work 100 feet high from earth?
interviewer: yes
Candidate how about 2 km -5 km high?
interviewer: yes
---
Candidate: What's the response time to tell the weather, can I assume it's extremely fast like 1ms or even lesser
interviewer: okay assume.
---
candidate: Can I assume that I can have an extremely high-speed drone, that says has the permissions from all government to fly over their country, each country can ask it to land anytime and inspect.
interviewer: okay let's assume that
---
candidate: I will make this drone that will carry this and fly over all countries and cities but needs to complete that circle in 30 days.
Interviewer: the world has this many countries and these many cities, overall world area is too huge, do you think it can complete all of it and come back in 30 days?
Candidate: it now becomes and maths and traversal problem. there are two ways to proceed.
in one operation we are able to cover 2*pi*30 miles, now calculate the entire earth's surface area.
how many scans will be needed?
I don't know how that numbers will be but it comes out to say less than 30(days)*24(hours)*60(seconds) then we cant use it for the entire earth.
then we will have to prioritize based on the usage.
If you think we cant travel faster, I will ask if we can this magic relic even higher up in the space and if it will still work? When gravity is less we can traverse even faster. I can have a satellite that travels super fast and takes all this data.
Also, I did not ask at the beginning when it takes 1 km or 5 km up from the ground, does the coverage increases? if yes then that reduces the size of the problem.
Just want to if you are looking for imagination or structure of thinking or exact maths number, I am assuming the combination of the first two.
Let me know if you want me to go into detail about maths.
Interviewer: I think that's okay
0 likes | 0 feedback
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