시간 제한 | 메모리 제한 | 제출 | 정답 | 맞힌 사람 | 정답 비율 |
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3 초 | 128 MB | 18 | 7 | 5 | 45.455% |
Gremlins have infested the farm. These nasty, ugly fairy-like creatures thwart the cows as each one walks from the barn (conveniently located at pasture_1) to the other fields, with cow_i traveling to from pasture_1 to pasture_i. Each gremlin is personalized and knows the quickest path that cow_i normally takes to pasture_i. Gremlin_i waits for cow_i in the middle of the final cowpath of the quickest route to pasture_i, hoping to harass cow_i.
Each of the cows, of course, wishes not to be harassed and thus chooses an at least slightly different route from pasture_1 (the barn) to pasture_i.
Compute the best time to traverse each of these new not-quite-quickest routes that enable each cow_i that avoid gremlin_i who is located on the final cowpath of the quickest route from pasture_1 to pasture_i.
As usual, the M (2 <= M <= 200,000) cowpaths conveniently numbered 1..M are bidirectional and enable travel to all N (3 <= N <= 100,000) pastures conveniently numbered 1..N. Cowpath i connects pastures a_i (1 <= a_i <= N) and b_i (1 <= b_i <= N) and requires t_i (1 <= t_i <= 1,000) time to traverse. No two cowpaths connect the same two pastures, and no path connects a pasture to itself (a_i != b_i). Best of all, the shortest path regularly taken by cow_i from pasture_1 to pasture_i is unique in all the test data supplied to your program.
By way of example, consider these pastures, cowpaths, and [times]:
1--[2]--2-------+ | | | [2] [1] [3] | | | +-------3--[4]--4 TRAVEL BEST ROUTE BEST TIME LAST PATH p_1 to p_2 1->2 2 1->2 p_1 to p_3 1->3 2 1->3 p_1 to p_4 1->2->4 5 2->4
When gremlins are present:
TRAVEL BEST ROUTE BEST TIME AVOID p_1 to p_2 1->3->2 3 1->2 p_1 to p_3 1->2->3 3 1->3 p_1 to p_4 1->3->4 6 2->4
4 5 1 2 2 1 3 2 3 4 4 3 2 1 2 4 3
3 3 6