三分

CZ写的三分模板

View Code

 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 }