【模板】单源最短路径（标准版）

Time cost：807ms

CODE：

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #include<algorithm>
 5 #include<queue>
 6 #define rep(i,a,n) for(int i = a;i <= n;i++)
 7 #define per(i,n,a) for(int i = n;i >= a;i--)
 8 #define inf 2147483647
 9 #define ms(a,b) memset(a,b,sizeof(a))
10 using namespace std;
11 typedef long long ll;
12 ll read() {
13     ll as = 0,fu = 1;
14     char c = getchar();
15     while(c < '0' || c > '9') {
16         if(c == '-') fu = -1;
17         c = getchar();
18     } 
19     while(c >= '0' && c <= '9') {
20         as = as * 10 + c - '0';
21         c = getchar();
22     }
23     return as * fu;
24 }
25 const int N = 400005;
26 //head
27 int m,n,s;
28 int head[N],cst[N],nxt[N],mo[N],cnt;
29 inline void add(int x,int y,int z) {
30     mo[++cnt] = y;
31     cst[cnt] = z;
32     nxt[cnt] = head[x];
33     head[x] = cnt;
34     return;
35 }
36 
37 struct node {
38     int idx,dis;
39     bool operator < (const node &other) const {
40         return dis > other.dis;
41     }
42 };
43 
44 priority_queue<node> q;
45 int dis[N];
46 bool vis[N];
47 void dijkstra() {
48     ms(dis,60);
49     ms(vis,0);
50     dis[s] = 0;
51     q.push((node){s,0});
52     while(!q.empty()) {
53         int x = q.top().idx;
54         q.pop(); 
55         if(vis[x]) continue;
56         vis[x] = 1;
57         for(int i = head[x];i;i = nxt[i]) {
58             int sn = mo[i];
59             //if(vis[sn]) continue;
60             if(dis[sn] > dis[x] + cst[i]) {
61                 dis[sn] = dis[x] + cst[i];
62                 q.push((node){sn,dis[sn]});
63             }
64         }
65     }
66     return;
67 }
68 
69 
70 int main() {
71     n = read();
72     m = read();
73     s = read();
74     rep(i,1,m) {
75         int x = read();
76         int y = read();
77         int w = read();
78         add(x,y,w);
79     }
80     dijkstra();
81     rep(i,1,n) printf("%d ",dis[i]);
82     puts("");
83     return 0;
84 }

 

posted @ 2018-10-03 22:35  白怀潇  阅读(182)  评论(0)    收藏  举报