uva1587

maksyuki 发表于 oj 分类,标签:
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Ivan works at a factory that produces heavy machinery. He has a simple job -- he knocks up wooden boxes of different sizes to pack machinery for delivery to the customers. Each box is a rectangular parallelepiped. Ivan uses six rectangular wooden pallets to make a box. Each pallet is used for one side of the box.

Joe delivers pallets for Ivan. Joe is not very smart and often makes mistakes -- he brings Ivan pallets that do not fit together to make a box. But Joe does not trust Ivan. It always takes a lot of time to explain Joe that he has made a mistake. Fortunately, Joe adores everything related to computers and sincerely believes that computers never make mistakes. Ivan has decided to use this for his own advantage. Ivan asks you to write a program that given sizes of six rectangular pallets tells whether it is possible to make a box out of them.

Input 

Input file contains several test cases. Each of them consists of six lines. Each line describes one pallet and contains two integer numbers w and h ( 1wh10 000) -- width and height of the pallet in millimeters respectively.

Output 

For each test case, print one output line. Write a single word POSSIBLE' to the output file if it is possible to make a box using six given pallets for its sides. Write a single word IMPOSSIBLE' if it is not possible to do so.

Sample Input 

1345 2584

2584 683

2584 1345

683 1345

683 1345

2584 683

1234 4567

1234 4567

4567 4321

4322 4567

4321 1234

4321 1234

Sample Output 

POSSIBLE

IMPOSSIBLE

 

题目类型:数学题

算法分析:由平行四面体的几何关系可知组成四面体的六个长方形必须两两长宽分别相等。这里将数据输入结构体数组后,将数组先按照h递增排序,然后按照w递增排序。然后进行简单的判断即可。注意重载小于号的方法及进行递增排序的方法,下面第一个代码是更好的实现