Intersection (HDU5120 + round-cross area)

Topic Links:

　　http://acm.hdu.edu.cn/showproblem.php?pid=5120

Topic:

Test instructions

　　Find the area where two rings intersect.

Ideas:

Two large circle area cross -2x large circle with small round area intersection + two small round area sex.

The code is implemented as follows:

1#include <Set>2#include <map>3#include <deque>4#include <ctime>5#include <stack>6#include <cmath>7#include <queue>8#include <string>9#include <cstdio>Ten#include <vector> One#include <iomanip> A#include <cstring> -#include <iostream> -#include <algorithm> the using namespacestd; -  -typedefLong LongLL; -typedef PAIR&LT;LL, Ll>PLL; +typedef PAIR&LT;LL,int>Pli; -typedef pair<int,int>PII; +typedef unsignedLong LongULL; A  at #defineLson rt<<1 - #defineRson rt<<1|1 - #defineNAME2STR (name) (#name) - #defineBug printf ("**********\n"); - #defineIO Ios::sync_with_stdio (FALSE); - #defineDebug (x) cout<< #x << "=[" <<x<< "]" <<endl; in #defineFIN freopen ("/home/dillonh/clionprojects/in.txt", "R", stdin); -  to Const DoubleEPS = 1e-8; + Const intMAXN = 1e5 +7; - Const intINF =0x3f3f3f3f; the Const DoublePI = ACOs (-1.0); * ConstLL INF =0x3f3f3f3f3f3f3f3fll; $ Panax Notoginseng intT, R, R; - intx1, x2, yy, y2; the  + DoubleCirinter (intX1,intY1,intR1,intX2,intY2,intR2)//formula of round intersection area A { the     DoubleD,s,t,a1,a2,s1,s2,s3; +     if(r1<r2) Swap (r1, r2); -D=sqrt ((x1-x2) * (X1-X2) + (y1-y2) * (Y1-y2));//Two center distance $     if(D&GT;=R1+R2)return 0;//two Yuan $     Else if(d<= (R1-R2))//Two circle included -s=pi*r2*R2; -     Else{//Two circle intersection theA1=acos ((R1*R1+D*D-R2*R2)/(2*R1*D));//half of the circle's Center angle -A2=acos ((R2*R2+D*D-R1*R1)/(2*R2*D));//half of the circle's Center angleWuyiS1=A1*R1*R1;//The fan area in the big circle theS2=A2*R2*R2;//The fan area in the small circle -S3=r1*sin (A1) *d;//two quadrilateral area of the center and two intersections WuS=S1+S2-S3;//area of round cross -     } About     returns; $ } -  - intMain () { - #ifndef Online_judge A FIN; + #endif thescanf"%d", &t); -     intIcase =0; $      while(t--) { thescanf"%d%d", &r, &R); thescanf"%d%d%d%d", &x1, &yy, &AMP;X2, &y2); the         DoubleAns = cirinter (x1, yy, R, x2, Y2, R)-2* Cirinter (x1, yy, R, x2, Y2, R) +cirinter (x1, yy, R, x2, Y2, R); theprintf"Case #%d:%.6f\n", ++icase, ans); -     } in     return 0; the}

Intersection (HDU5120 + round-cross area)