POJ 3255 Roadblocks

#include <iostream>
#include<queue>
#include<vector>
#define MAX_N 100005
#define INF 1000000
using namespace std;
struct edge
{
int to;
int cost;
};
typedef pair<int ,int> P;
vector<edge> g[MAX_N];
int dist1 [MAX_N];
int dist2 [MAX_N];
priority_queue<P,vector<P>,greater<P> > que;

void solve(int N)
{
int i;
for(i=0;i<MAX_N;i++)
{
dist1[i]=INF;
dist2[i]=INF;
}
dist1[0]=0;
que.push(make_pair(0,1));
while(!que.empty())
{
P p=que.top();
que.pop();
int v=p.second,d=p.first;
if(dist2[v]<d)
continue;
for(i=0; i<g[v].size(); i++)
{
edge &e=g[v][i];
int d2=d+e.cost;
if(dist1[e.to]>d2)
{
swap(dist1[e.to],d2);
que.push(make_pair(dist1[e.to],e.to));
}
if(dist2[e.to]>d2&&dist1[e.to]<d2)
{
dist2[e.to]=d2;
que.push(make_pair(dist2[e.to],e.to));
}

}

}
cout<<dist2
<<endl;

}

int main()
{
int N,R;
int ta,tb,tc;
int i;
edge e;
cin>>N>>R;
for(i=0;i<R;i++)
{
cin>>ta>>tb>>tc;
e.to=tb;e.cost=tc;
g[ta].push_back(e);
e.to=ta;
g[tb].push_back(e);
}
solve(N);

return 0;
}