【模板】单源最短路径 堆优化的dijkstra

 1 #include<queue> 
 2 #include<cstdio>
 3 #include<iostream>
 4 using namespace std;
 5 const int maxn = 100010, maxm = 500020, inf = 1<<30;
 6 int num = 0, n, m, s;
 7 int head[maxm], dis[maxn];
 8 bool vis[maxn];
 9 priority_queue< pair<int, int> >q;
10 struct edge {
11     int nxt, to, dis;
12 }e[maxm<<1];
13 int read() {
14     char ch = getchar(); int x = 0, f = 1;
15     while(ch<‘0‘||ch>‘9‘) {if(ch == ‘-‘) f = -1;ch = getchar();}
16     while(ch>=‘0‘&&ch<=‘9‘) {x = x*10+ch-‘0‘; ch = getchar();}
17     return x*f;
18 }
19 void add(int from, int to, int dis) {
20     e[++num].nxt = head[from];
21     e[num].to = to;
22     e[num].dis = dis;
23     head[from] = num;
24 }
25 void dijkstra() {
26     for(int i = 1; i <= n; i++) {
27         dis[i] = inf;
28         vis[i] = 0;
29     }
30 //    vis[s] = 1;
31     dis[s] = 0;
32     q.push(make_pair(0, s));
33     while(q.size()) {
34         int u = q.top().second;
35         q.pop();
36         if(vis[u]) continue;
37         vis[u] = 1;
38         for(int i = head[u]; i; i = e[i].nxt) {
39             int v = e[i].to;
40             if(dis[v] > dis[u]+e[i].dis) {
41                 dis[v] = dis[u]+e[i].dis;
42                 q.push(make_pair(-dis[v], v));
43             }
44         }
45     }
46 }
47 
48 int main() {
49     scanf("%d%d%d", &n, &m, &s);
50     for(int i = 1; i <= m; i++) {
51         int f, g, k;
52         f = read(), g = read(), k = read();
53         add(f, g, k);
54     }
55     dijkstra();
56     for(int i = 1; i <= n; i++) 
57         printf("%d ", dis[i]);
58     return 0;
59 }