ZOJ-3488-Conic Section【8th浙江省赛】

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3488-Conic Section

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                    Time Limit: 2 Seconds      Memory Limit: 65536 KB

The conic sections are the nondegenerate curves generated by the intersections of a plane with one or two nappes of a cone. For a plane perpendicular to the axis of the cone, a circle is produced. For a plane that is not perpendicular to the axis and that intersects only a single nappe, the curve produced is either an ellipse or a parabola. The curve produced by a plane intersecting both nappes is a hyperbola.

Input

There are multiple test cases. The first line of input is an integer T ≈ 10000 indicating the number of test cases.

Each test case consists of a line containing 6 real numbers a, b, c, d, e, f. The absolute value of any number never exceeds 10000. It’s guaranteed that a2+c2>0, b=0, the conic section exists and it is non-degenerate.

Output

For each test case, output the type of conic section ax2+bxy+cy2+dx+ey+f=0. See sample for more details.

Sample Input
5
1 0 1 0 0 -1
1 0 2 0 0 -1
0 0 1 1 0 0
1 0 -1 0 0 1
2 0 2 4 4 0

Sample Output
circle
ellipse
parabola
hyperbola
circle

题目链接：ZOJ-3488

题目大意：给出ax2+bxy+cy2+dx+ey+f=0的系数，问是什么图形

题目思路：判断a,c即可。时隔一年再写这题，还是掉到了坑里面去 注意，数字范围是实数！

以下是代码：

#include <iostream>#include <cstdio>#include <cmath>#include <vector>#include <cstring>#include <algorithm>#include <string>#include <set>#include <functional>#include <numeric>#include <sstream>#include <stack>#include <map>#include <queue>#include<iomanip>using namespace std;int main(){    int t;    cin >> t;    while(t--)    {        double a,b,c,d,e,f;        cin >> a >> b >> c >> d >> e >> f;        if (a == c) cout << "circle\n";        if (a * c > 0 && a != c) cout << "ellipse\n";        if (a == 0 || c == 0) cout << "parabola\n";        if (a * c < 0 && a != c) cout << "hyperbola\n";    }    return 0;}