You have an × grid filled with non-negative numbers. Find a path from top-left to bottom-right that minimizes the sum of numbers along the path. You can only move right or down at each step. Unlike Grid Paths where you count paths, here you want the cheapest one.
This is a classic grid DP problem. Before reading on, think: what should dp[][] represent? Before reading the solution, try to identify the base case and recursive relationship yourself.