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c#median
rikket
rikket

Reputation: 2407

Most efficient way to find median of three integers

Which the most effecient way to find a median of three integer number without using an array like the example below:

int[] median = {int a, int b,int c};
Array.Sort(median); 

int medianValue = median[1];

Upvotes: 3

Views: 6217

Answers (3)

ajz
ajz

Reputation: 255

The following is verbose, but I believe that it minimizes the number of comparisons. Note: it is possible that number of comparisons might not be the only factor in performance.

static int Median(int num1, int num2, int num3)
{
    if (num1 < num2)
    {
        if (num2 <= num3)
            return num2;
        if (num1 < num3)
            return num3;
        return num1;
    }
    else
    {
        if (num1 <= num3)
            return num1;
        if (num2 < num3)
            return num3;
        return num2;
    }
}

Upvotes: 0

user3590011
user3590011

Reputation: 15

int Median(int num1, int num2, int num3)
{
    if ((num2 < num1 && num1 < num3) || (num2 > num1 && num1 > num3))
    {
        return num1;
    }

    if ((num1 < num2 && num2 < num3) || (num1 > num2 && num2 > num3))
    {
        return num2;
    }

    return num3;
}

Upvotes: 0

Bathsheba
Bathsheba

Reputation: 234795

The fastest way I know of is to use

max(min(a, b), min(max(a, b), c))

I'm trusting that C# has optimisations for min and max taking two arguments. This will be quicker than taking if statements due to branching.

There are other tricks: you can implement min and max using XOR and < but I doubt that has any benefits on modern architectures.

Upvotes: 16

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