POJ 3169 Layout

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 const int maxn = 1010;
18 struct arc{
19     int to,w;
20     arc(int x = 0,int y = 0){
21         to = x;
22         w = y;
23     }
24 };
25 vector<arc>g[maxn];
26 queue<int>q;
27 int d[maxn],cnt[maxn],N,ML,MD;
28 bool used[maxn];
29 void spfa(){
30     for(int i = 1; i <= N; i++){
31         d[i] = INF;
32         cnt[i] = 0;
33         used[i] = false;
34     }
35     d[1] = 0;
36     used[1] = true;
37     q.push(1);
38     while(!q.empty()){
39         int u = q.front();
40         q.pop();
41         used[u] = false;
42         for(int i = 0; i < g[u].size(); i++){
43             if(d[g[u][i].to] > d[u] + g[u][i].w){
44                 d[g[u][i].to] = d[u] + g[u][i].w;
45                 if(!used[g[u][i].to]){
46                     q.push(g[u][i].to);
47                     used[g[u][i].to] = true;
48                     cnt[g[u][i].to]++;
49                     if(cnt[g[u][i].to] > N){
50                         puts("-1");
51                         return;
52                     }
53                 }
54             }
55         }
56     }
57     if(d[N] == INF) puts("-2");
58     else printf("%d\n",d[N]);
59 }
60 int main(){
61     int i,u,v,w;
62     while(~scanf("%d %d %d",&N,&ML,&MD)){
63         for(i = 0; i <= N; i++) g[i].clear();
64         for(i = 0; i < ML; i++){
65             scanf("%d %d %d",&u,&v,&w);
66             g[u].push_back(arc(v,w));
67         }
68         for(i = 0; i < MD; i++){
69             scanf("%d %d %d",&u,&v,&w);
70             g[v].push_back(arc(u,-w));
71         }
72         for(i = 1; i < N; i++)
73             g[i+1].push_back(arc(i,0));
74         spfa();
75     }
76     return 0;
77 }