HDU 1078 - FatMouse and Cheese.
Problem : Given a map. Must start at (0, 0). At each position (x, y), one can goto another position (x+i, y) or (x, y+i) (-k<=i<=k) and the destionation must has larger value than the previous place. Find the maximum sum of the value by reached place.
Solution : The map must be the DAG, since the next place must has the larger value than the previous one. Thus it's a raw DAG DP, to get the maximum sum of the path.