Courier Route Ledger

A campus courier service receives several city maps before a hiring simulation. Each map has numbered checkpoints and two-way roads with positive travel times. For every map, the courier starts at checkpoint 1 and must report the minimum possible travel time to the final checkpoint n. If the final checkpoint cannot be reached, report -1 for that map. Input Format: The first line contains t, the number of independent maps. Each map begins with n and m. The next m lines contain u, v, and w, meaning checkpoints u and v are connected by a two-way road taking w minutes. Output Format: For each map, print one integer: the minimum travel time from checkpoint 1 to checkpoint n, or -1 when no route exists.