Walking with Boost Stations (Greedy Simulation)

Problem: Total Walking Distance with Boost Stations Start at position 0 and deliver goods to target on a 1D line. There are m station positions p[i]. Rules: You may walk from current goods position cur to a station p[i] (must satisfy p[i] >= cur). This walking distance adds to the total. After reaching that station, a drone boosts the goods forward by a fixed distance d, updating cur = p[i] + d. Repeat until cur >= target. If at some point cur < target and no station with p[i] >= cur exists, you must walk directly to target. Compute the total walking distance. Input (one common OA format) Line 1: m target d Line 2: m integers p[i] Output One integer: total walking distance. Example Input 3 25 10 0 10 20 Output 0