赤裸裸的最短路，需要注意下枚舉過程就好了。直接貼上別人的代碼，發現他的代碼挺符合我的風格，以后就這樣寫了。

?

#include?<bits/stdc++.h>

using?namespace?std;

struct?node{
????int?y,z,id;
????node(){}
????node(int?y,int?z,int?id):y(y),z(z),id(id){}
};
vector<node>?e[300100];

int?n,m,u;
int?f[300100];
int?ed[300100];
long?long?dis[300100];
vector<int>?ans;
const?long?long?inf?=?(long?long)300100*1000000000;

int?main(){
????cin?>>n?>>m;
????for?(int?i=1;i<=m;i++){
????????int?x,y,z;
????????cin?>>?x>>y>>z;
????????ed[i]=z;
????????e[x].push_back(node(y,z,i));
????????e[y].push_back(node(x,z,i));
????}
????cin?>>?u;
????queue<int>?q;
????q.push(u);
????for?(int?i=1;i<=n;i++)?dis[i]=inf;
????//for?(int?i=1;i<=n;i++)?cout<<dis[i]<<endl;
????dis[u]=0;
????while?(!q.empty()){
????????int?now?=?q.front();
????????q.pop();
????????for?(int?i=0;i<e[now].size();i++){
????????????int?v?=?e[now][i].y;
????????????if?(dis[now]+e[now][i].z<dis[v]?||?dis[now]+e[now][i].z==dis[v]?&&?e[now][i].z<ed[f[v]]){
????????????????f[v]=e[now][i].id;
????????????????dis[v]=dis[now]+e[now][i].z;
????????????????q.push(v);
????????????}
????????}
????}
????long?long?cnt=0;
????for?(int?i=1;i<=n;i++)
????????if?(f[i]!=0)?cnt+=ed[f[i]],ans.push_back(f[i]);
????sort(ans.begin(),ans.end());
????cout?<<?cnt<<endl;
????for(int?i=0;i<ans.size();i++){
????????if?(i>0)?cout<<"?";
????????cout?<<?ans[i];
????}
????return?0;

}?

轉載于:https://www.cnblogs.com/acvc/p/4517508.html

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