Statement

Everybody knows that Eng. Dog is the Messina's bridge manager: his duty is designing the new bridge over the Strait of Messina. One of the major challenges is to move a heavy load, the bridge's main span, from the base camp to the building site. Unfortunately, the payload is way too heavy to be moved by hand; therefore, he needs to operate a series of cranes. The base camp is at considered to be at position 0, the destination is D meters away along a straight line and N cranes can be operated. The i-th crane is located at X_i meters from the base camp and has an arm R_i meters long. The crane can perform the following actions: (1) move the head in [X_i - R_i, X_i-1] if it points to the left, or in [X_i + 1, X_i + R_i] if it points to the right (extremes included); (2) pick-up the load if it's directly under the head; (3) put down the load directly under the head...