Poj--2546（两圆相交）

2014-11-28 23:55:59

思路：两圆相交模板题，找了一发模板，挺好的。

 1 /*************************************************************************
 2     > File Name: 2546.cpp
 3     > Author: Nature
 4     > Mail: 564374850@qq.com 
 5     > Created Time: Fri 28 Nov 2014 11:39:45 PM CST
 6 ************************************************************************/
 7 
 8 #include <cstdio>
 9 #include <cstring>
10 #include <cstdlib>
11 #include <cmath>
12 #include <vector>
13 #include <map>
14 #include <set>
15 #include <stack>
16 #include <queue>
17 #include <iostream>
18 #include <algorithm>
19 using namespace std;
20 #define lp (p << 1)
21 #define rp (p << 1|1)
22 #define getmid(l,r) (l + (r - l) / 2)
23 #define MP(a,b) make_pair(a,b)
24 typedef long long ll;
25 const int INF = 1 << 30;
26 const double PI = acos(-1.0);
27 
28 struct circle{
29     double x,y,r;
30 };
31 
32 double Cal_area(circle a,circle b){
33     double d = sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
34     if(d >= a.r + b.r)
35         return 0;
36     double r = min(a.r,b.r);
37     if(d <= fabs(b.r - a.r))
38         return PI * r * r;
39     double a1 = acos((a.r * a.r + d * d - b.r * b.r) / (2.0 * a.r * d));
40     double a2 = acos((b.r * b.r + d * d - a.r * a.r) / (2.0 * b.r * d));
41     double ans = -d * a.r * sin(a1);
42     ans += a1 * a.r * a.r + a2 * b.r * b.r;
43     return ans;
44 }
45 
46 int main(){
47     circle a,b;
48     while(scanf("%lf%lf%lf%lf%lf%lf",&a.x,&a.y,&a.r,&b.x,&b.y,&b.r) != EOF){
49         printf("%.3f\n",Cal_area(a,b));
50     }
51     return 0;
52 }

 

posted @ 2014-11-28 23:56  Naturain  阅读(126)  评论(0)    收藏  举报