Ideal Path UVA

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仿照刘汝佳的代码用vector却超时。。。

只能自己再写一个用队列实现的。。

而且还要注意这个地方要vis数组。。（按理说应该知道走过的路自然不会再走啊。。不懂。。。。）

#include<cstdio>#include<cstring>#include<algorithm>#include<queue>#include<string>#include<cstring>#include<iomanip>#include<iostream>#include<stack>#include<cmath>#include<map>#include<vector>#define ll long long#define inf 0x3f3f3f3f#define INF 1000000000#define bug1 cout<<"bug1"<<endl;#define bug2 cout<<"bug2"<<endl;#define bug3 cout<<"bug3"<<endl;using namespace std;int n,m;int tol;const int maxn=100000 + 5;struct Edge{    int v,nxt,w;}edge[maxn*4];int head[maxn];int vis[maxn];int d[maxn];void addedge(int u,int v,int w){    edge[tol].v=v;    edge[tol].w=w;    edge[tol].nxt=head[u];    head[u]=tol++;}void rev_bfs(){    memset(vis,0,sizeof(vis));    memset(d,0,sizeof(d));    queue<int>que;    que.push(n);    vis[n]=1;    d[n]=0;    while(!que.empty()){        int u=que.front();que.pop();        for(int i=head[u];i!=-1;i=edge[i].nxt){            int v=edge[i].v;            if(vis[v])continue;            vis[v]=1;            d[v]=d[u]+1;            que.push(v);        }    }}vector<int>ans;void bfs(){    memset(vis,0,sizeof(vis));    ans.clear();    queue<int >que;    queue<int >que2;    queue<int>tmp;    queue<int>tmp1;    que.push(1);     vis[1]=1;    while(!que.empty()){        int min_color=INF;        while(!que.empty()){            int t=que.front();que.pop();            tmp.push(t);            tmp1.push(t);//一分为二，第一个是用来找min_color的，第二个就是用来走下一个节点的        }        while(!tmp.empty()){        int u=tmp.front();tmp.pop();        if(u==n)break;        for(int i=head[u];i!=-1;i=edge[i].nxt){            int v=edge[i].v;            if(d[v]==d[u]-1){                min_color=min(min_color,edge[i].w);            }        }        }        ans.push_back(min_color);        while(!tmp1.empty()){            int u=tmp1.front();tmp1.pop();        for(int i=head[u];i!=-1;i=edge[i].nxt){            int v=edge[i].v;            if(d[v]==d[u]-1&&!vis[v]&&edge[i].w==min_color){                if(v==n)return;                vis[v]=1;                que2.push(v);            }        }        }        if(que.empty()){            while(!que2.empty()){                int t=que2.front();que2.pop();                que.push(t);            }        }    }}int main(){    while(scanf("%d%d", &n, &m) == 2){            tol=0;        memset(head,-1,sizeof(head));        for(int i=1;i<=m;++i){            int u,v,w;            scanf("%d%d%d",&u,&v,&w);            addedge(u,v,w);            addedge(v,u,w);        }        rev_bfs();        bfs();         printf("%d\n", ans.size());  printf("%d", ans[0]);  for(int i = 1; i < ans.size(); i++) printf(" %d", ans[i]);  printf("\n");    }}

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