C. The Child and Toy

http://codeforces.com/contest/437/problem/C

贪心，按照自身的费用从大到小拿，费用相等先后顺序不影响结果

至于为什么嘛……试试这么想想，每一条边的消费是必算的，整个过程是拿点消边，最后图上是不存在边的。而每条边的消费又只有两种可能，那么拿消费大的点就是个最优解，保证所有牵连边消费都选择最小

 

import java.util.*;

public class Main {
    static final int MAX = Integer.MAX_VALUE;

    public static void main(String[] args) {
        Scanner io = new Scanner(System.in);
        int n = io.nextInt(), m = io.nextInt();

        PriorityQueue<P> q = new PriorityQueue<>();
        int[] a = new int[1000 + 50];
        for (int i = 1; i <= n; i++) q.add(new P(i, a[i] = io.nextInt()));

        ArrayList<Integer>[] c = new ArrayList[1000 + 50];
        for (int i = 0; i < c.length; i++) c[i] = new ArrayList<>();
        for (int i = 0, aa, bb; i < m; i++) {
            aa = io.nextInt();
            bb = io.nextInt();
            c[aa].add(bb);
            c[bb].add(aa);
        }

        int sum = 0, p;
        int[] vis = new int[1000 + 50];
        while (!q.isEmpty()) {
            p = q.poll().n;
            vis[p] = 1;
            for (int i = 0, cc; i < c[p].size(); i++) {
                cc = c[p].get(i);
                if (vis[cc] == 0) sum += a[cc];
            }
        }
        System.out.println(sum);
    }

    static class P implements Comparable<P> {
        int n, m;

        @Override
        public int compareTo(P o) {
            return -m + o.m;
        }

        public P(int n, int m) {
            this.n = n;
            this.m = m;
        }
    }
}