C - Can you solve this equation? HDU - 2199（二分水题）

Now,given the equation 8x^4 + 7x^3 + 2x^2 + 3x + 6 == Y,can you

find its solution between 0 and 100; Now please try your lucky. Input

The first line of the input contains an integer T(1<=T<=100) which

means the number of test cases. Then T lines follow, each line has a

real number Y (fabs(Y) <= 1e10); Output For each test case, you should

just output one real number(accurate up to 4 decimal places),which is

the solution of the equation,or “No solution!”,if there is no solution

for the equation between 0 and 100. Sample Input

2

100

-4

Sample Output

1.6152

No solution!

#include<iostream>

#include<algorithm>

#include<cstdio>

#include<cmath>

using namespace std;

#define ll long long

#define db double

const int Len = 1e5+10;

db Cal(db m)

{

    return 8 * pow(m, 4) + 7 * pow(m, 3) + 2 * pow(m, 2) + 3 * m + 6;

}

int main()

{

    //freopen("A.txt","r",stdin);

    int t;

    cin >> t;

    while(t --)

    {

        int n;

        scanf("%d", &n);

        db l = 0, r = 100;

        if(Cal(0) > n || Cal(100) < n)

            cout << "No solution!\n";

        else

        {

            db m;

            while(r - l >= 1e-10)

            {

                m = (l + r)/2;

                if(Cal(m) > n)

                    r = m;

                else

                    l = m;

            }

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

        }

    }

    return 0;

}

巴特西

C - Can you solve this equation? HDU - 2199（二分水题）

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