#include #include #include #include using namespace std; int N,M; vector >G[1<<17]; main() { cin>>N>>M; for(int i=0;i>a>>b>>c; G[a-1].push_back(make_pair(b-1,c)); G[b-1].push_back(make_pair(a-1,c)); } vector >d1(N,make_pair(-9e18,-2e9)); vectord2(N,9e18); d1[0]=make_pair(0,0); priority_queue,int> >P; P.push(make_pair(make_pair(0,0),0)); while(!P.empty()) { pairp=P.top().first; int u=P.top().second; P.pop(); if(d1[u].first>p.first)continue; for(int i=0;iq=p; int v=G[u][i].first; if(G[u][i].second<-q.second) { q.first-=G[u][i].second; if(d1[G[u][i].first]q.second) { d1[G[u][i].first]=q; P.push(make_pair(q,v)); } } else { q.first+=q.second; q.second=-G[u][i].second; if(d1[G[u][i].first]=q.second) { d1[G[u][i].first]=q; P.push(make_pair(q,v)); } } } } d2[0]=0; priority_queue >P2; P2.push(make_pair(0,0)); while(!P2.empty()) { long c=-P2.top().first; int u=P2.top().second; P2.pop(); if(d2[u]next) { d2[v]=next; P2.push(make_pair(-next,v)); } } } for(int i=0;i