题目描述

A vicious thunderstorm has destroyed some of the wires of the farm's electrical power grid! Farmer John has a map of all $N$ ($2\le N \le 1000$) of the powerpoles, which are conveniently numbered $1\ldots N$ and located on integer plane coordinates $(x_i,y_i)$ ($-100000 \le x_i \le 100000, -100000 \le y_i \le 100000$).

Some $W$ ($1 \le W \le 10000$) power wires connect pairs of power poles $P_i$ and $P_j$ ($1 \le Pi \le N, 1 \le Pj \le N$).

He needs to get power from pole $1$ to pole $N$ (which means that some series of wires can traverse from pole $1$ to pole $N$, probably through some intermediate set of poles).

Given the locations of the $N$ poles and the list of remaining power wires, determine the minimum length of power wire required to restore the electrical connection so that electricity can flow from pole $1$ to pole $N$. No wire can be longer than some real number $M$ ($0.0 < M \le 200000.0$).

As an example, below on the left is a map of the $9$ poles and $3$ wires after the storm. For this task, $M = 2.0$. The best set of wires to add would connect poles $4$ and $6$ and also poles $6$ and $9$.

   After the storm              Optimally reconnected
3  . . . 7 9 . . . . .          3  . . . 7 9 . . . . .
                                          /
2  . . 5 6 . . . . . .          2  . . 5 6 . . . . . .
                                        /
1  2-3-4 . 8 . . . . .          1  2-3-4 . 8 . . . . .
   |                               |
0  1 . . . . . . . . .          0  1 . . . . . . . . .

   0 1 2 3 4 5 6 7 8 9             0 1 2 3 4 5 6 7 8 9

The total length is then $1.414213562 + 1.414213562 = 2.828427124$.

POINTS: 350

输入格式

Line $1$: Two space-separated integers: $N$ and $W$.

Line $2$: A single real number: $M$.

Lines $3\ldots N+2$: Each line contains two space-separated integers: $x_i$ and $y_i$.

Lines $N+3\ldots N+2+W$: Two space-separated integers: $P_i$ and $P_j$.

输出格式

Line 1: A single integer on a single line. If restoring connection is impossible, output -1. Otherwise, output a single integer that is $1000$ times the total minimum cost to restoreelectricity. Do not perform any rounding; truncate the resulting product.

题目大意

一场邪恶的暴风雨毁坏了农夫约翰的输电网中的一些电线！农夫约翰有一张包含了所有 $n$（$2\le n\le 1000$）个电能中转点的地图，中转点编号为 $1\ldots n$，第 $i$ 个点的坐标为 $(x_i,y_i)$（$-100000\le x_i\le 100000,-100000\le y_i\le 100000$）。

有 $w$（$1<=w<=10000$）条电线仍然保存着没被暴风雨破坏，每条电线连接着两个电能中转点 $p_i,p_j$（$1\le p_i\le n,1\le p_j\le n$）。

他希望从第一个电能中转点把电导入第 $n$ 个（可能通过一些中间的电能中转点，应当有一组电线连接 $1$ 和 $n$ ）。

给出 $n$ 个电能中转点的坐标和幸存的电线，请确定最少需要架设的电线总长度，但请注意，架设过程中，对于单条电线而言，其长度不应超过$m$（$0.0\le m\le 200000.0$）

给出一个例子，在下面，左边是一个包含 $9$ 个电能中转电和 $3$ 条幸存电线的地图。在这个任务中，规定 $m=2.0$。最佳的架设方案是连接 $6$ 和 $4$，以及 $6$ 和 $9$。

   After the storm              Optimally reconnected
3  . . . 7 9 . . . . .          3  . . . 7 9 . . . . .
                                          /
2  . . 5 6 . . . . . .          2  . . 5 6 . . . . . .
                                        /
1  2-3-4 . 8 . . . . .          1  2-3-4 . 8 . . . . .
   |                               |
0  1 . . . . . . . . .          0  1 . . . . . . . . .

   0 1 2 3 4 5 6 7 8 9             0 1 2 3 4 5 6 7 8 9

总长度是 $1.414213562 + 1.414213562 = 2.828427124$。

9 3 
2.0 
0 0 
0 1 
1 1 
2 1 
2 2 
3 2 
3 3 
4 1 
4 3 
1 2 
2 3 
3 4 

2828 

提示

Just as in the diagram above.

As above.