Start by defining the DP state `dp[i][w]` as the maximum value achievable with the first `i` items and a knapsack capacity of `w`.

Derive the recurrence relation for `dp[i][w]` considering both the inclusion and exclusion of the `i-th` item, accounting for unlimited reuse.

Optimize the space complexity by reducing the 2D DP table to a 1D array, leveraging the fact that `dp[i][w]` depends only on `dp[i-1][w]` and `dp[i][w - weight[i]]`.