BZOJ3564 [SHOI2014] signal growth meter

First, the elliptical long axis to the x-axis, and then the x-axis in proportion to shrink back, so it becomes the smallest circle coverage problem, on the board ... Just do it.

1 /**************************************************************2 problem:35643 User:rausen4 language:c++5 result:accepted6 time:256 Ms7 memory:2380 KB8 ****************************************************************/9  Ten#include <cstdio> One#include <cmath> A   - using namespacestd; -typedefDoubleLF; the Const intN = 5e4 +5; - ConstLF pi = ACOs (-1.0); - ConstLF EPS = 1e-7; -   +Inlineintread (); -   +Template <classT>T Sqr (t x) { A     returnX *x; at } -   - structPoint { - lf x, y; - Point () {} - Point (LF _x, LF _y): X (_x), Y (_y) {} in       -Inlinevoid Get() { tox = Read (), y =read (); +     } -InlinevoidRev (Lf a) { the         Staticlf tx, Ty; *tx = x * COS (a)-Y * sin (a), Ty = x * sin (a) + y *cos (a); $x = tx, y =Ty;Panax Notoginseng     } -       theInline pointoperator+ (ConstPoint &p)Const { +         returnPoint (x + p.x, y +p.y); A     } theInline pointoperator- (ConstPoint &p)Const { +         returnPoint (x-p.x, Y-p.y); -     } $Inline pointoperator/(LF T)Const { $         returnPoint (x/t, Y/t); -     } -Inline LFoperator* (ConstPoint &p)Const { the         returnX * p.y-y *p.x; -     }Wuyi       theFriend Inline LF Dis2 (ConstPoint &p) { -         returnSQR (LF) p.x) +SQR (LF) p.y); Wu     } -Friend Inline Point work (ConstPoint &a,ConstPoint &b,ConstPoint &c) { About         StaticPoint p, Q, res; $         StaticLF D, AB, BC, AC; -p = b-a, q = c-a, d = p * Q *2; -         if(Fabs (d) <EPS) { -AB = Dis2 (b-a), BC = DIS2 (c-b), ac = Dis2 (C-a); A             if(AB-BC >= EPS && ab-ac >= EPS)return(A + B)/2; +             if(Bc-ab >= EPS && bc-ac >= EPS)return(b + C)/2; the             return(A + C)/2; -         } $         returnPoint (Dis2 (P) * Q.Y-DIS2 (q) * p.y, DIS2 (q) * P.X-DIS2 (P) * q.x)/D +A; the     } the } P[n], c[n]; the   the intN, CNT; - LF Alpha, P; in   the inline LF min_cover () { the     Static intI, J, K; About     StaticLF rad2; theRad2 = CNT =0; the      for(i =1; I <= N; ++i)if(Dis2 (P[i]-c[cnt]) >rad2) { theC[CNT] = P[i], rad2 =0.0; +          for(j =1; J < I; ++J)if(Dis2 (P[j]-c[cnt]) >rad2) { -C[CNT] = (P[i] + p[j])/2.0, rad2 = Dis2 (P[i]-c[cnt]); the              for(k =1; K < J; ++K)if(Dis2 (P[k]-c[cnt]) >rad2)BayiC[CNT] = Work (P[i], p[j], p[k]), rad2 = Dis2 (P[i]-c[cnt]); the         } the     } -     returnsqrt (rad2); - } the    the   the intMain () { the     inti; -n =read (); the      for(i =1; I <= N; ++i) P[i].Get(); theAlpha = (LF) read ()/180.0* pi, P =read (); the      for(i =1; I <= N; ++i)94P[i].rev (-alpha), p[i].x/=P; theprintf"%.3lf\n", Min_cover ()); the     return 0; the }98   AboutInlineintRead () { -     Static intx, SGN;101     Static Charch;102x =0, SGN =1, ch =GetChar ();103      while(Ch <'0'||'9'<ch) {104         if(ch = ='-') SGN =-1; theCH =GetChar ();106     }107      while('0'<= CH && Ch <='9') {108x = x *Ten+ CH-'0';109CH =GetChar (); the     }111     returnSGN *x; the}

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(P.S. Rank.1 Liquid! In Circles ~ in Circles ~)

BZOJ3564 [SHOI2014] signal growth meter