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  • codeforce 630N Forecast

    N. Forecast
    time limit per test
    0.5 seconds
    memory limit per test
    64 megabytes
    input
    standard input
    output
    standard output

    The Department of economic development of IT City created a model of city development till year 2100.

    To prepare report about growth perspectives it is required to get growth estimates from the model.

    To get the growth estimates it is required to solve a quadratic equation. Since the Department of economic development of IT City creates realistic models only, that quadratic equation has a solution, moreover there are exactly two different real roots.

    The greater of these roots corresponds to the optimistic scenario, the smaller one corresponds to the pessimistic one. Help to get these estimates, first the optimistic, then the pessimistic one.

    Input

    The only line of the input contains three integers a, b, c ( - 1000 ≤ a, b, c ≤ 1000) — the coefficients of ax2 + bx + c = 0equation.

    Output

    In the first line output the greater of the equation roots, in the second line output the smaller one. Absolute or relative error should not be greater than 10 - 6.

    Examples
    input
    1 30 200
    output
    -10.000000000000000
    -20.000000000000000

    解方程求两个根
    运用公式法x1=(-1*b-sqrt(b*b-4*a*c))/(2*a);
    x2=(-1*b+sqrt(b*b-4*a*c))/(2*a);

    #include<stdio.h>
    #include<string.h>
    #include<string>
    #include<math.h>
    #include<algorithm>
    #define LL long long
    #define PI atan(1.0)*4
    #define DD double
    #define MAX 10010
    #define mod 100
    #define dian 1.000000011
    #define INF 0x3f3f3f
    using namespace std;
    int main()
    {
    	DD a,b,c,x,y;
    	DD x1,x2;
    	while(scanf("%lf%lf%lf",&a,&b,&c)!=EOF)
    	{
    		x=(-1*b+sqrt(b*b-4*a*c))/(2*a);
    		y=(-1*b-sqrt(b*b-4*a*c))/(2*a);
    		x1=max(x,y);
    		x2=min(x,y);
    		printf("%lf
    %lf
    ",x1,x2);
    	}
    	return 0;
    }
    

      

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  • 原文地址:https://www.cnblogs.com/tonghao/p/5251242.html
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