Problem 44480. The average of the second largest values

Given a matrix, find the average of the second largest values in each row. The same value does not exist on a row.

Example: input x = [1 2 3 4;8 7 6 5;9 0 1 4] >>> output y = (3+7+4) / 3

Solve

Last Solution submitted on Jul 05, 2020

John BG on 23 Feb 2018

this

x2=x
[max1,ind1]=max(x2,[],2)
x2(sub2ind(size(x),[1:3],ind1'))=NaN
[max2,ind2]=max(x2,[],2)
y=mean(x2(sub2ind(size(x),[1:size(x,1)],ind2')))

solves the question yet the checker returns not a valid answer.

John BG on 23 Feb 2018

the following 4 lines solve this question

[max1,ind1]=max(x,[],2)
x(sub2ind(size(x),[1:3],ind1'))=NaN
[max2,ind2]=max(x,[],2)
y=mean(x(sub2ind(size(x),[1:3],ind2')))

yet the online checker returns not a valid answer

basic matlab basics