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| #include<iostream>
#include<cmath>
using namespace std;
#define pi acos(-1.0)
typedef struct node {
int x;
int y;
} point;
double AREA(point a, double r1, point b, double r2) {
double d = sqrt((a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y));
if (d >= r1+r2)
return 0;
if (r1>r2) {
double tmp = r1;
r1 = r2;
r2 = tmp;
}
if(r2 - r1 >= d)
return pi*r1*r1;
double ang1=acos((r1*r1+d*d-r2*r2)/(2*r1*d));
double ang2=acos((r2*r2+d*d-r1*r1)/(2*r2*d));
return ang1*r1*r1 + ang2*r2*r2 - r1*d*sin(ang1);
}
int main() {
point a, b;
a.x=2, a.y=2;
b.x=7, b.y=2;
double result = AREA(a, 3, b, 5);
printf("%lf\n", result);
return 0;
}
|
