二维spfa模板

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int maxn=100+10,maxm=10000+10,inf=0x3f3f3f3f;
 4     int w,n,m;
 5 struct Edge{
 6     int to,next,lenth,money;
 7 }e[maxm];
 8 int head[maxn],tot=0;
 9 void Insert(int a,int b,int c,int d){
10     e[++tot].to=b;
11     e[tot].lenth=c;
12     e[tot].money=d;
13     e[tot].next=head[a];
14     head[a]=tot;
15 }
16 int d[maxn][1000+10];
17 void spfa(int x){
18     queue< pair<int,int> > q;
19     int vis[maxn][1000+10];
20     memset(d,0x3f,sizeof(d));
21     memset(vis,0,sizeof(vis));
22     q.push(make_pair(x,0));
23     vis[x][0]=1;
24     d[x][0]=0;
25     while(!q.empty()){
26         pair<int,int> now=q.front();
27         q.pop();
28         int u=now.first;
29         int s=now.second;
30         vis[u][s]=0;
31         for(int i=head[u];i;i=e[i].next){
32             int v=e[i].to;
33             if(s+e[i].money>w) continue;
34             if(d[v][s+e[i].money]>d[u][s]+e[i].lenth){
35                 d[v][s+e[i].money]=d[u][s]+e[i].lenth;
36                 if(!vis[v][s+e[i].money]){
37                     vis[v][s+e[i].money]=1;
38                     q.push(make_pair(v,s+e[i].money));
39                 }
40             }
41         }
42     }
43 }
44 int main(){
45     scanf("%d%d%d",&w,&n,&m);
46     for(int i=1;i<=m;i++){
47         int u,v,l,cost;
48         scanf("%d%d%d%d",&u,&v,&l,&cost);
49         Insert(u,v,l,cost);
50     }
51     spfa(1);
52     int ans=inf;
53     for(int i=0;i<=w;i++){
54         ans=min(ans,d[n][i]);
55     }
56     if(ans==inf) printf("NO\n");
57     else printf("%d\n",ans);
58     return 0;
59 }