Code:
#include <queue>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 400005
#define ll long long
#define setIO(s) freopen(s".in","r",stdin)
using namespace std;
ll d[N];
int n,edges;
int hd[N],to[N<<1],nex[N<<1],val[N<<1],done[N];
void addedge(int u,int v,int c)
{
nex[++edges]=hd[u],hd[u]=edges,to[edges]=v,val[edges]=c;
swap(u,v);
nex[++edges]=hd[u],hd[u]=edges,to[edges]=v,val[edges]=c;
}
struct Point
{
int x,y,id;
}e[N];
bool cmpx(Point a,Point b)
{
return a.x<b.x;
}
bool cmpy(Point a,Point b)
{
return a.y<b.y;
}
struct Node
{
int u;
ll dis;
Node(int u=0,ll dis=0):u(u),dis(dis){}
bool operator<(Node b) const
{
return b.dis<dis;
}
};
priority_queue<Node>q;
void Dijkstra()
{
int s=1;
memset(d,0x3f,sizeof(d));
for(d[s]=0,q.push(Node(s,0));!q.empty();)
{
Node e=q.top(); q.pop();
int u=e.u,i,v;
if(done[u]) continue;
done[u]=1;
for(i=hd[u];i;i=nex[i])
{
v=to[i];
if(d[v]>d[u]+val[i])
{
d[v]=d[u]+val[i];
q.push(Node(v,d[v]));
}
}
}
}
int main()
{
int i,j,k;
// setIO("input");
scanf("%d",&n);
for(i=1;i<=n;++i)
{
int x,y;
scanf("%d%d",&e[i].x,&e[i].y), e[i].id=i;
}
sort(e+1,e+1+n,cmpx);
for(i=2;i<=n;++i)
addedge(e[i-1].id,e[i].id,e[i].x-e[i-1].x);
sort(e+1,e+1+n,cmpy);
for(i=2;i<=n;++i)
{
addedge(e[i-1].id,e[i].id,e[i].y-e[i-1].y);
}
Dijkstra();
printf("%lld\n",d[n]);
return 0;
}