You say that this simple question but I think for a long time, alas may still be too much food, tears, pulled down (sad) ┭┮﹏┭┮
Because of all this problem is a topic online solution, I can not understand the reason, is to ask the gods to hkk "It is clear that the practice of" rejected. . Obviously all the gods do question it?
Finally yy himself out a new approach should be called the new rigorous scientific understanding of the method, I do not know is not a correct idea
First, try to optimize the construction side, to a point, they even a $ \ min (\ Delta x, \ Delta y) $ edges, is there any way to go with some other side instead of the value?
To construct a grid graph if all points, the same meaning of the questions found $ X $ point moves on a vertical column is not easily spent, across adjacent columns have spent $ \ Delta x $, $ y $ empathy .
Thus, even an arbitrary side, $ \ $ min in the $ \ Delta x $ can be represented by a certain number of successive columns across each row takes a price. $ \ Delta y $ express across several lines every time it takes the sum of the cross.
In this way, the edges can be marked, and even then with a solution to a problem edge method prevailing, found that even $ 0 $ edges between peers or the same column, adjacent rows or columns as long as the election of a representative point even the edges, so take the shortest path.
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<cmath> 6 #include<queue> 7 #define dbg(x) cerr << #x << " = " << x <<endl 8 using namespace std; 9 typedef long long ll; 10 typedef double db; 11 typedef pair<int,int> pii; 12 template<typename T>inline T _min(T A,T B){return A<B?A:B;} 13 template<typename T>inline T _max(T A,T B){return A>B?A:B;} 14 template<typename T>inline char MIN(T&A,T B){return A>B?(A=B,1):0;} 15 template<typename T>inline char MAX(T&A,T B){return A<B?(A=B,1):0;} 16 template<typename T>inline void _swap(T&A,T&B){A^=B^=A^=B;} 17 template<typename T>inline T read(T&x){ 18 x=0;int f=0;char c;while(!isdigit(c=getchar()))if(c=='-')f=1; 19 while(isdigit(c))x=x*10+(c&15),c=getchar();return f?x=-x:x; 20 } 21 const int N=200000+7; 22 struct thxorz{int to,nxt,w;}G[N<<3]; 23 int Head[N],tot; 24 inline void Addedge(int x,int y,int z){ 25 G[++tot].to=y,G[tot].nxt=Head[x],Head[x]=tot,G[tot].w=z; 26 G[++tot].to=x,G[tot].nxt=Head[y],Head[y]=tot,G[tot].w=z; 27 } 28 int n; 29 struct stothx{int x,y,id;}A[N]; 30 inline bool cmp1(stothx a,stothx b){return a.x<b.x;} 31 inline bool cmp2(stothx a,stothx b){return a.y<b.y;} 32 priority_queue<pii,vector<pii>,greater<pii> > pq; 33 int dis[N]; 34 #define y G[j].to 35 inline void dij(){ 36 memset(dis,0x3f,sizeof dis);pq.push(make_pair(dis[1]=0,1)); 37 while(!pq.empty()){ 38 int x=pq.top().second,d=pq.top().first;pq.pop(); 39 if(d^dis[x])continue; 40 if(x==n)return; 41 for(register int j=Head[x];j;j=G[j].nxt)if(MIN(dis[y],d+G[j].w))pq.push(make_pair(dis[y],y)); 42 } 43 } 44 #undef y 45 int main(){//freopen("test.in","r",stdin);//freopen("test.ans","w",stdout); 46 read(n); 47 for(register int i=1;i<=n;++i)read(A[i].x),read(A[i].y),A[i].id=i; 48 sort(A+1,A+n+1,cmp1); 49 for(register int i=1;i<n;++i)Addedge(A[i].id,A[i+1].id,A[i+1].x-A[i].x); 50 sort(A+1,A+n+1,cmp2); 51 for(register int i=1;i<n;++i)Addedge(A[i].id,A[i+1].id,A[i+1].y-A[i].y); 52 dij(); 53 printf("%d\n",dis[n]); 54 return 0; 55 }