1030. Travel Plan (30)

1030. Travel Plan (30)
dijkstra记录所有最短路径，dfs筛选最优路径即可

#include <cstdio>#include <vector>#define N 500+1#define INF 999999999std::vector<std::vector<int>> path(N);std::vector<int> sp;std::vector<int> ans;int n,m,s,d,mincost=INF,distance=0;int a[N][N],dist[N],visited[N],cost[N][N];void dfs(std::vector<std::vector<int>> &path,int v){    sp.push_back(v);    if(v==s)    {        int curcost=0;        auto r=sp.begin();        auto f=sp.begin()+1;        while(f!=sp.end())        {            curcost+=cost[*r][*f];            r=f;++f;        }        if(curcost<mincost)        {            mincost=curcost;            ans=sp;        }        return;    }    for(auto it=path[v].begin();it!=path[v].end();++it)    {        dfs(path,*it);        sp.pop_back();    }}int main(){    scanf("%d %d %d %d",&n,&m,&s,&d);    for(int i=0;i<n;++i)    {        for(int j=0;j<n;++j)        {            if(i==j)                a[i][j]=0;            else                a[i][j]=INF;        }    }    for(int i=0;i<m;++i)    {        int u,v,dis,ct;        scanf("%d %d %d %d",&u,&v,&dis,&ct);        a[u][v]=a[v][u]=dis;        cost[u][v]=cost[v][u]=ct;    }    for(int i=0;i<n;++i)    {        if(a[i][s]<INF)            path[i].push_back(s);        dist[i]=a[s][i];    }    int i,j,v,w;    visited[s]=1;    for(i=1;i<n;++i)    {        int min=INF;        for(j=0;j<n;++j)        {            if(min>dist[j]&&!visited[j])            {                min=dist[j];                v=j;            }        }        visited[v]=1;        for(w=0;w<n;++w)        {            if(!visited[w]&&a[v][w]<INF)            {                if(dist[w]>dist[v]+a[v][w])                {                    dist[w]=dist[v]+a[v][w];                    path[w].clear();                    path[w].push_back(v);                }                else if(dist[w]==dist[v]+a[v][w])                    path[w].push_back(v);            }        }    }    dfs(path,d);    auto it=ans.end()-1;    while(it>=ans.begin())    {        if(it>ans.begin())        {            auto r=it-1;            distance+=a[*it][*r];        }        printf("%d ",*it);        it--;    }    printf("%d %d",distance,mincost);    return 0;}