1 #include <stdio.h>
 2 #include <iostream>
 3 #include <string.h>
 4 #include <algorithm>
 5 #define N 20
 6 #define inf 100000000
 7 #define _clr(a,val) (memset(a,val,sizeof(a)))
 8
 9 using namespace std;
10
11 int vis[N];
12 int head[N];
13 struct node
14 {
15     int a,b,c,p,r;
16     int next;
17 }point[N];
18 int n,m;
19 int minn;
20 void dfs(int x,int sum)
21 {
22     if(sum > minn || vis[x] > n) return;  // 当一个节点被访问n次时，就没必要再访问了
23     if(x == n)
24     {
25         if(sum < minn) minn = sum;
26         return ;
27     }
28     int t = head[x];
29     while(t != -1)
30     {
31         vis[point[t].b] ++;
32         if(vis[point[t].c] > 0) dfs(point[t].b,sum + point[t].p);
33         else dfs(point[t].b , point[t].r + sum);
34         vis[point[t].b] --;
35         t = point[t].next;
36     }
37 }
38 int main()
39 {
40     int i;
41     //freopen("data.txt","r",stdin);
42     while(scanf("%d%d",&n,&m) != EOF)
43     {
44         _clr(vis,0);
45         _clr(head,-1);
46         for(i = 0; i < m; i++)
47         {
48             scanf("%d%d%d%d%d",&point[i].a,&point[i].b,&point[i].c,&point[i].p,&point[i].r);
49             point[i].next = head[point[i].a];
50             head[point[i].a] = i;
51         }
52         minn = inf;
53         vis[1] = 1;
54         dfs(1,0);
55         if(minn == inf) printf("impossible\n");
56         else printf("%d\n",minn);
57     }
58     return 0;
59 }

 1 #include <stdio.h>
 2 #include <iostream>
 3 #include <string.h>
 4 #include <queue>
 5 #include <algorithm>
 6 #define N 10010
 7 #define inf 100000000
 8 #define _clr(a,val) (memset(a,val,sizeof(a)))
 9
10 using namespace std;
11
12 struct node
13 {
14     int point;
15     int len;
16     int cost;
17     friend bool operator < (node a,node b)  // 定义顺序
18     {
19         return a.len > b.len;
20     }
21 };
22 struct tnode
23 {
24     int f,t,l,c;
25     int next;
26 }eage[N];
27 int s,d,r;
28 int head[N];
29 void bfs()
30 {
31     node tem;
32     int flag = 0;
33     tem.point = 1, tem.len = tem.cost = 0;
34     priority_queue<node>qu;
35     qu.push(tem);
36     while(!qu.empty())
37     {
38         //cout<<"999\n";
39         node temp = qu.top();
40         qu.pop();
41         if(temp.point == d)
42         {
43             printf("%d\n",temp.len);
44             flag = 1;
45             break;  //找到了就输出并退出
46         }
47         int i = head[temp.point];
48         while(i != -1)
49         {
50             node ttem;
51             ttem.point = eage[i].t, ttem.len = temp.len + eage[i].l, ttem.cost = temp.cost + eage[i].c;
52             if(ttem.cost <= s)
53             {
54                 qu.push(ttem);
55             }
56             i = eage[i].next;
57         }
58     }
59     if(!flag) printf("-1\n");
60     return ;
61 }
62 int main()
63 {
64     int i;
65     //freopen("data.txt","r",stdin);
66     while(scanf("%d%d%d",&s,&d,&r) != EOF)
67     {
68         _clr(head,-1);
69         for(i = 0; i < r; i++)
70         {
71             scanf("%d%d%d%d",&eage[i].f,&eage[i].t,&eage[i].l,&eage[i].c);
72             eage[i].next = head[eage[i].f], head[eage[i].f] = i;
73         }
74         bfs();
75     }
76     return 0;
77 }