Codeforces Round 250 (Div. 2)
C
The Child and Toy
Codeforces
1400
原题
← BD →
翻译中…

On Children's Day, the child got a toy from Delayyy as a present. However, the child is so naughty that he can't wait to destroy the toy.

翻译中…

The toy consists of $*n*$ parts and $*m*$ ropes. Each rope links two parts, but every pair of parts is linked by at most one rope. To split the toy, the child must remove all its parts. The child can remove a single part at a time, and each remove consume an energy. Let's define an energy value of part $*i*$ as $*v*_{*i*}$. The child spend $*v*_{*f*_{1}} + *v*_{*f*_{2}} + ... + *v*_{*f*_{*k*}}$ energy for removing part $*i*$ where $*f*_{1}, *f*_{2}, ..., *f*_{*k*}$ are the parts that are directly connected to the $*i*$-th and haven't been removed.

翻译中…

Help the child to find out, what is the minimum total energy he should spend to remove all $*n*$ parts.

翻译中…

Input

翻译中…

The first line contains two integers $*n*$ and $*m*$ ($1 ≤ *n* ≤ 1000$; $0 ≤ *m* ≤ 2000$). The second line contains $*n*$ integers: $*v*_{1}, *v*_{2}, ..., *v*_{*n*}$ ($0 ≤ *v*_{*i*} ≤ 10^{5}$). Then followed $*m*$ lines, each line contains two integers $*x*_{*i*}$ and $*y*_{*i*}$, representing a rope from part $*x*_{*i*}$ to part $*y*_{*i*}$ ($1 ≤ *x*_{*i*}, *y*_{*i*} ≤ *n*; *x*_{*i*} ≠ *y*_{*i*}$).

翻译中…

Consider all the parts are numbered from $1$ to $*n*$.

翻译中…

Output

翻译中…

Output the minimum total energy the child should spend to remove all $*n*$ parts of the toy.

翻译中…

Note

翻译中…

One of the optimal sequence of actions in the first sample is:

翻译中…
  • First, remove part $3$, cost of the action is $20$.
  • Then, remove part $2$, cost of the action is $10$.
  • Next, remove part $4$, cost of the action is $10$.
  • At last, remove part $1$, cost of the action is $0$.
翻译中…

So the total energy the child paid is $20 + 10 + 10 + 0 = 40$, which is the minimum.

翻译中…

In the second sample, the child will spend $400$ no matter in what order he will remove the parts.

翻译中…

样例

Input #1
4 3
10 20 30 40
1 4
1 2
2 3
Output #1
40
InputCopy OutputCopy
Input #2
4 4
100 100 100 100
1 2
2 3
2 4
3 4
Output #2
400
InputCopy OutputCopy
Input #3
7 10
40 10 20 10 20 80 40
1 5
4 7
4 5
5 2
5 7
6 4
1 6
1 3
4 3
1 4
Output #3
160
InputCopy OutputCopy
题目信息
题号
437C
时间限制
1 s
内存限制
256 MB
标签
图论
贪心
排序

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。