Problem 45881. Reindex a vector (★★)

(copy of Prob. 676)

You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero.

For example:

N = [1 3 2 7];
IDX= [2 3 4 6];

then

y_correct = [0 1 3 2 0 7];

N(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...

If N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.