POJ 2187 N points output 2 points of the maximum distance squared

Rotating Jam

Sample Input

4
0 0
0 1
1 1
1 0
Sample Output

2

1# include <iostream>2# include <cstdio>3# include <cstring>4# include <algorithm>5# include <string>6# include <cmath>7# include <queue>8# define LLLong Long9 using namespacestd;Ten  One struct Point A { -     intx, y; -Point (int_x =0,int_y =0) the     { -x = _x; y =_y; -     } -Pointoperator-(ConstPoint &b)Const +     { -         returnPoint (x-b.x, Y-b.y); +     } A     int operator^(ConstPoint &b)Const at     { -         returnx*b.y-y*b.x; -     } -     int operator*(ConstPoint &b)Const -     { -         returnx*b.x + y*b.y; in     } -     voidinput () to     { +scanf"%d%d",&x,&y); -     } the }; * //the square of the distance $ intDist2 (point a,point B)Panax Notoginseng { -     return(A-B) * (A-b); the } + //****** two-dimensional convex bag, int*********** A Const intMAXN =50010; the Point LIST[MAXN]; + intStack[maxn],top; - BOOL_cmp (Point p1,point p2) $ { $     intTMP = (p1-list[0]) ^ (p2-list[0]); -     if(tmp >0)return true; -     Else if(TMP = =0&& Dist2 (p1,list[0]) <= Dist2 (p2,list[0])) the     return true; -     Else return false;Wuyi } the voidGraham (intN) - { Wu Point p0; -     intK =0; AboutP0 = list[0]; $      for(inti =1; I < n;i++) -         if(P0.y > List[i].y | | (P0.y = = List[i].y && p0.x >list[i].x)) -         { -P0 =List[i]; AK =i; +         } theSwap (list[k],list[0]); -Sort (list+1, list+n,_cmp); $     if(n = =1) the     { thetop =1; thestack[0] =0; the         return; -     } in     if(n = =2) the     { thetop =2; Aboutstack[0] =0; stack[1] =1; the         return; the     } thestack[0] =0; stack[1] =1; +top =2; -      for(inti =2; I < n;i++) the     {Bayi          while(Top >1&& the((list[stack[top-1]]-list[stack[top-2]]) ^ (list[i]-list[stack[top-2]]) <=0) thetop--; -stack[top++] =i; -     } the } the //rotate Jam to find the maximum distance squared between two points the intRotating_calipers (Point p[],intN) the { -     intAns =0; the Point v; the     intCur =1; the      for(inti =0; I < n;i++)94     { thev = p[i]-p[(i+1)%n]; the          while((v^ (p[(cur+1)%n]-p[cur]) <0) theCur = (cur+1)%N;98ans = max (Ans,max (Dist2 (p[i],p[cur)), Dist2 (p[(i+1)%n],p[(cur+1)%N] )); About     } -     returnans;101 }102 Point P[MAXN];103 intMain ()104 { the     //freopen ("In.txt", "R", stdin);106     intN;107      while(SCANF ("%d", &n) = =1)108     {109          for(inti =0; I < n;i++) the list[i].input ();111 Graham (n); the          for(inti =0; i < top;i++) P[i] =List[stack[i]];113printf"%d\n", Rotating_calipers (p,top)); the     } the     return 0; the}

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POJ 2187 N points output 2 points of the maximum distance squared