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No.788 Moving Trucks

レベル : / 実行時間制限 : 1ケース 2.000秒 / メモリ制限 : 512 MB / 標準ジャッジ問題
タグ : (AC するまで非表示) / 解いたユーザー数 79
作問者 : tatyam / テスター : Shuz*
お気に入りにしたユーザー ProblemId : 2526 / 自分の提出
問題文最終更新日: 2020-06-09 16:25:11
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yukicoder contest 205 (順位表) の他の問題:

Problem Statement

The country of tatyam has $N$ intersections numbered from $1$ to $N$ and $M$ roads connecting them; intersection $a_i$ and intersection $b_i$ are connected by a road of length $c_i$.
A festival is held in the country of tatyam, and at the festival trucks may be rotated by 90 degrees. In preparation for the upcoming festival, tatyam plans to gather the trucks at a single intersection.
tatyam owns one tow truck, and the tow truck can lift and carry one truck.
The tow truck is parked at intersection $L$, and $t_i$ trucks are parked at intersection $i$.
Find the travel distance when the tow truck is moved with the shortest possible travel distance so that all trucks are gathered at a single intersection.

Input

$N\ M\ L$
$t_1\ \cdots\ t_N$
$a_1\ b_1\ c_1$
$\vdots$
$a_m\ b_m\ c_m$

$2\leq N\leq 2000$
$N-1\leq M\leq 2000$
$0\leq t_i\leq 2000$
$1\leq\sum t_i$
$1\leq L,\ a_i,\ b_i\leq N$
$1\leq c_i\leq 10^6$
The graph formed by the given intersections and roads is connected.

Output

Output the travel distance when the tow truck is moved with the shortest possible travel distance so that all trucks are gathered at a single intersection.
If the trucks are already at a single intersection, output 0.
Print a newline at the end.

Sample

Sample 1
Input
4 3 1
0 1 1 1
1 2 1
1 3 2
1 4 3
Output
12

For example, the following is a shortest way.
Move from vertex 1 to vertex 2 and lift a truck
Move from vertex 2 to vertex 1 and put down the truck
Move from vertex 1 to vertex 3 and lift a truck
Move from vertex 3 to vertex 1 and put down the truck
Move from vertex 1 to vertex 4 and lift a truck
Move from vertex 4 to vertex 1 and put down the truck

Sample 2
Input
5 5 1
0 2 1 1 2
1 2 1
1 3 2
2 4 2
3 4 2
4 5 2
Output
19

For example, the following is a shortest way.
1→2
2→4
4→2
2→4
4→3
3→4
4→5
5→4
4→5
5→4

Sample 3
Input
7 9 1
1 1 1 1 1 1 1
1 7 3
2 3 3
2 5 4
3 4 5
3 5 1
3 7 6
4 6 2
5 6 7
6 7 9
Output
53

For example, the following is a shortest way.
1→7
7→3
3→2
2→3
3→4
4→3
3→5
5→3
3→4
4→6
6→4
4→3
3→7
7→3

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