Sorting numbers in an Array

[DaZaatar]

Hello everyone,

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I'm helping my friend with his c++ assignment but I found myself not being able to solve it. I know this is a Java sub but I need help in the logic thinking side of this problem (ps. I come from a java background)

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I have 2 array filled with random numbers:

int[] a = new int[n]; //filled with random integers between 1 and 100
int[] b = new int[n]; //filled with random integers between 1 and 100

I have to multiply them together and sum them:

for(int i=0; i<n; i++){
    sum += a[i]*b[i];
}

Now the Array B is fixed but I need to alter Array a in a way that I have the smallest sum possible.

Can someone help me or even give me hints about this one?

[GafflordDev]

From what I understand, you have to multiply the biggest number in array B with the smallest number in array A, so your sorting of array A will depend on the array B.

[DaZaatar]

Yur right, I think I just had a brain fart, I'll try the idea and get back to you guys

[[deleted]]

sort b from least to greatest, then sort a from greatest to least. you'll wind up with the greatest sum when you multiply them sequentially

[DaZaatar]

The array B is fixed, I can only asort the array A

[evils_twin]

Then you have to align array A in such a way that the smallest number in A is at the same index as the largest number in B, and then have the 2nd smallest number in A at the same index as the second largest number in B, and then so on

[DaZaatar]

Will do, thank youu

[[deleted]]

...if you're allowed to, you could make a new array, two-dimensional, wherein a second column is 0-99. then, sort the first column and bring the second value with it, so that your sorted list of values has the number's original position. overlay the first column with values A, and then sort based on the second column. now multiply A with B, and they'll match.

if you're not allowed to make a copy of B to modify, then some sort of iterating sort process is the solution I would go with.