Question:
Given two sorted sequences in increasing order, $X$ and $Y$. $Y$ is of size $k$ and $X$ is of size $m$.
I would like to find a subset of $X$, $i.e$, $X'$ of size $k$, and considering the following optimization problem:$$d(Y,X') = \sum_{j=1}^{k}(y_{j}-x'_{j})^{2}$$ And $X'$ is a subset of $X$ of size $k$, $y_{j} \text{ and } x'_{j}$ is element in $Y$ and $X'$. I would like to find the subset of $X$, to reach the minimum of $d(Y,X')$.
Note that $X'$ could have $k!$ numbers of arrangements, so its order is totally unknown.
What I have came up with so far:
I would like to approach it using Dynamic Programming, and I think I would first compute the squared distance between each element in $Y$ and $X$, but I'm having trouble in determining what is the subproblem and how to solve ths using DP. Thank you!
Update: The $X'$ could be sorted, which means we could aim at finding a sorted subset of $X$.