HDU 3714

 1 最大值最小问题，三分。。。。竟然排第六当时。。。。。

 2 #include<stdio.h>

 3 

 4 #include<string.h>

 5 #define max 10000+10

 6 #define Max(x,y) (x>y?x:y)

 7 #define Min(x,y) (x<y?x:y)

 8 #define inf 1e-8

 9 

10 typedef long long LL;

11 int a[max],b[max],c[max];

12 int t,n;

13 

14 double func(int a,int b,int c,double x){

15     return a*x*x+b*x+c;

16 }

17 

18 double solve(double x){

19         double res=func(a[0],b[0],c[0],x);

20         for(int i=1;i<n;i++){

21             res=Max(res,func(a[i],b[i],c[i],x));

22         }

23         return res;

24 }

25 

26 int main(){

27     scanf("%d",&t);

28     while(t--){

29         scanf("%d",&n);

30         for(int i=0;i<n;i++){

31             scanf("%d%d%d",&a[i],&b[i],&c[i]);

32         }

33         double left=0.0,right=1000.0;

34         while(right-left>inf){

35             double mid=(left+right)*0.5;

36             double mmid=(left+mid)*0.5;

37             double res1=solve(mid);

38             double res2=solve(mmid);

39             if(res2-res1>inf){

40                 left=mmid;

41             }

42             else{

43                 right=mid;

44             }

45         }

46         double ans=solve(left);

47         printf("%.4lf\n",ans);

48     }

49 }