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Asked: 2026-06-16T19:27:02+00:00

My sincere apologies for such a naive question. I know this is simple. But

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My sincere apologies for such a naive question. I know this is simple. But nothing comes to my mind now.

I am using C++. I’m a bit concerned about efficiency since this is targeted for an embedded hardware with very less processing power and RAM.

I have 2 integer arrays with 50 members local to a function. I need to determine what is the corresponding number in the second array when an element in the first array is specified and vice versa. I have the information that the element provided to me for look-up belongs to which array i.e. array 1 or array 2.

Ex : Array1 => 500 200 1000 300 .....

 Array2 => 250 170 500  400 .....

Input 500 , Output will be 250

Input 400 , Output will be 300

input 200 , Output will be 170 and so on

I think an array look-up will be least efficient. Is stl::map the best option or do i have to look for any efficient search algorithms? I would like to know if you have to do this, which option you will be choosing.

Any thoughts?

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1 Answer

  1. Editorial Team

    You can use std::map for readability and a little efficiency as well, though in your case efficiency is of small matter

    std::map<int,int> mapping;
.... //populate 
cout <<mapping[200]; //170

    This is only 1 way (Array 1 -> Array 2) though. Im not sure if any easier way to do the other way, but create a second map.

    To support reverse lookup, or going from (Array 2 -> Array 1), Reverse map lookup suggests using Boost.Bimap

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