三分

CZ写的三分模板
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 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <stdlib.h>
 4 #include <math.h>
 5 #define eps 1e-9
 6 double a,b;
 7 double getsum(double c)
 8 {
 9     double p,sum = 0;
10     p = (a+b+c)/2;
11     sum += sqrt(p*(p-a)*(p-b)*(p-c));
12     sum += c*c/4;
13     return sum;
14 }
15 int main()
16 {
17     double mid1,mid2,start,end,sq1,sq2;
18     while(scanf("%lf%lf",&a,&b)!=EOF)
19     {
20         start = 0;
21         end = a+b;
22         while(start+eps < end)
23         {
24             mid1 = (start+end)/2;
25             mid2 = (mid1+end)/2;
26             sq1 = getsum(mid1);
27             sq2 = getsum(mid2);
28             if(sq1 > sq2-eps)
29                 end = mid2;
30             else
31                 start = mid1;
32         }
33         printf("%.9lf\n",getsum(start));
34     }
35     return 0;
36 }