http://codeforces.com/contest/450/problem/D
先对公路集合求最短路，再判断铁路集合是否可再次更新d[]，如果可以就r--
1 public class Main {
2
3 public static void main(String[] args) {
4 IO io = new IO();
5 int n = io.nextInt(), m = io.nextInt(), k = io.nextInt();
6 ArrayList<int[]>[] g = new ArrayList[100000 + 100];
7 for (int i = 0; i < g.length; i++) g[i] = new ArrayList<>();
8
9 for (int i = 0; i < m; i++) {
10 int x = io.nextInt(), y = io.nextInt(), c = io.nextInt();
11 g[x].add(new int[]{y, c});
12 g[y].add(new int[]{x, c});
13 }
14
15 PriorityQueue<P>q=new PriorityQueue<>();
16 //w==0：公路集合最短路，w==1，铁路更新最短路
17 q.add(new P(0,0,1));
18 int[]d=new int[100000+100];
19 Arrays.fill(d,-1);
20
21 for (int i = 0; i < k; i++) {
22 int y=io.nextInt(),c=io.nextInt();
23 q.add(new P(c,1,y));
24 }
25
26 int r=k;
27 while (!q.isEmpty()){
28 P p=q.poll();
29 int c=p.c,w=p.w,x=p.x;
30 if (d[x]!=-1)continue;
31 if (w==1)r--;
32 d[x]=c;
33 for (int i = 0; i < g[x].size(); i++) {
34 int y=g[x].get(i)[0],cc=g[x].get(i)[1];
35 if (d[y]==-1)q.add(new P(c+cc,0,y));
36 }
37 }
38 io.println(r);
39 }
40
41 static class P implements Comparable<P> {
42 int c, w, x;
43
44 public P(int c, int w, int x) {
45 this.c = c;
46 this.w = w;
47 this.x = x;
48 }
49
50 @Override
51 public int compareTo(P o) {
52 if (o.c != c) return c - o.c;
53 if (o.w != w) return w - o.w;
54 if (o.x != x) return x - o.x;
55 return 0;
56 }
57 }
58
59
60 }