九度OnlineJudge之1002：Grading

题目描述：

    Grading hundreds of thousands of Graduate Entrance Exams is a hard work. It is even harder to design a process to make the results as fair as possible. One way is to assign each exam problem to 3 independent experts. If they do not agree to each other, a judge is invited to make the final decision. Now you are asked to write a program to help this process.
    For each problem, there is a full-mark P and a tolerance T(<P) given. The grading rules are:
    • A problem will first be assigned to 2 experts, to obtain G1 and G2. If the difference is within the tolerance, that is, if |G1 - G2| ≤ T, this problem's grade will be the average of G1 and G2.
    • If the difference exceeds T, the 3rd expert will give G3.
    • If G3 is within the tolerance with either G1 or G2, but NOT both, then this problem's grade will be the average of G3 and the closest grade.
    • If G3 is within the tolerance with both G1 and G2, then this problem's grade will be the maximum of the three grades.
    • If G3 is within the tolerance with neither G1 nor G2, a judge will give the final grade GJ.

输入：

    Each input file may contain more than one test case.
    Each case occupies a line containing six positive integers: P, T, G1, G2, G3, and GJ, as described in the problem. It is guaranteed that all the grades are valid, that is, in the interval [0, P].

输出：

    For each test case you should output the final grade of the problem in a line. The answer must be accurate to 1 decimal place.

样例输入：

20 2 15 13 10 18

样例输出：

        14.0

#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;

int max(int a,int b,int c)
{
return a>b?(a>c?a:c):b;      
}


int main()
{

int P,T,G1,G2,G3,GJ;
while(cin>>P>>T>>G1>>G2>>G3>>GJ)
{
   float grade=0;
   if(fabs(G1-G2)<=T) grade =  (G1+G2)/2.0;
   else
   if(fabs(G1-G3)<=T && fabs(G2-G3)>T) grade= (G3+G1)/2.0;
   else
   if(fabs(G2-G3)<=T && fabs(G1-G3)>T) grade= (G3+G2)/2.0;
   else
   if(fabs(G1-G3)<=T && fabs(G2-G3)<=T) grade = max(G1,G2,G3);
   else  grade=GJ;
       
   cout<<fixed<<setprecision(1)<<grade<<endl;    
       
       
       
}




  //system("pause");
	return 0;
}