bzoj 1579: [Usaco2009 Feb]Revamping Trails 道路升级

→题目链接←

一眼分层图...

然而我还是写挂了好几次qwq

代码：

#include<iostream>#include<cstdio>#include<vector>#include<queue>#include<cstring>using namespace std;struct node{int to,len;};struct node1{int now,ceng,len;node1(int x,int y,int z){now=x,ceng=y,len=z;}friend bool operator < (node1 a,node1 b){return a.len>b.len;}};int n,m,k;vector<node>v[10010];int dis[22][10010];bool vis[22][10010];priority_queue<node1>q;void link(int x,int y,int z){node t;t.to=y;t.len=z;v[x].push_back(t);t.to=x;v[y].push_back(t);}int main(){memset(vis,0,sizeof(vis));scanf("%d%d%d",&n,&m,&k);for(int i=0; i<m; i++){int x,y,z;scanf("%d%d%d",&x,&y,&z);link(x,y,z);}for(int i=0; i<=k; i++){for(int j=1; j<=n; j++){dis[i][j]=(1<<30);}}for(int i=0; i<=k; i++)dis[i][1]=0;q.push(node1(1,0,0));while(!q.empty()){node1 t=q.top();q.pop();if(vis[t.ceng][t.now])continue;vis[t.ceng][t.now]=true;for(int i=0; i<v[t.now].size(); i++){int to=v[t.now][i].to;int len=v[t.now][i].len;if(dis[t.ceng][to]>t.len+len){dis[t.ceng][to]=t.len+len;q.push(node1(to,t.ceng,t.len+len));}if(t.ceng+1<=k && dis[t.ceng+1][to]>t.len){dis[t.ceng+1][to]=t.len;q.push(node1(to,t.ceng+1,t.len));} }vis[t.ceng][t.now]=false;}int ans=(1<<30);for(int i=0; i<=k; i++)ans=min(ans,dis[i][n]);printf("%d\n",ans);return 0;}