Equations（数学，水）

最新推荐文章于 2021-03-02 11:59:32 发布

原创最新推荐文章于 2021-03-02 11:59:32 发布 · 579 阅读

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文章标签：

#integer #numbers #input #each #output #c

本文探讨了如何通过输入三个整数a、b、c来确定二次方程ax^2 + bx + c = 0的实数解数量，并提供了一个C++代码示例。包括了对a为0的特殊情况进行处理。

Equations

Time Limit: 1000/1000 MS (Java/Others) Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 689 Accepted Submission(s): 315

Problem Description

All the problems in this contest totally bored you. And every time you get bored you like playing with quadratic equations of the form a*X ² + b*X + c = 0. This time you are very curious to know how many real solutions an equation of this type has.

Input

The first line of input contains an integer number Q, representing the number of equations to follow. Each of the next Q lines contains 3 integer numbers, separated by blanks, a, b and c, defining an equation. The numbers are from the interval [-1000,1000].

Output

For each of the Q equations, in the order given in the input, print one line containing the number of real solutions of that equation. Print “INF” (without quotes) if the equation has an infinite number of real solutions.

Sample Input

Sample Output

  
   1
2
INF

Author

Mugurel Ionut Andreica

Source

Politehnica University of Bucharest Local Team Contest 2007

Recommend

lcy

只要注意a为0的情况就ok

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#define LL long long
#define maxi 2147483647
#define maxl 9223372036854775807
#define dg cout << "Here!" << endl;
using namespace std;

int main()
{
    int q, a, b, c, flag;
    cin >> q;
    while(q--)
    {
        cin >> a >> b >> c;
        if(!a)
        {
            if(!b)
            {
                if(!c) flag = 3;
                else flag = 0;
            }
            else flag = 1;
        }
        else
        {
            a = b * b - 4 * a * c;
            if(!a) flag = 1;
            else if(a > 0) flag = 2;
            else flag = 0;
        }
        if(!flag) puts("0");
        else if(flag == 1) puts("1");
        else if(flag == 2) puts("2");
        else puts("INF");
    }
    return 0;
}