Equations（数学，水）

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*X² + 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

3 1 0 0 1 0 -1 0 0 0

 

 

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;
}