学校自己挂的题目。。。我也不知道是哪里的。。。

Broken line

Time Limit:250MS     Memory Limit:4096KB     64bit IO Format:%I64d & %I64u

Submit Status

Description

There is a closed broken line on a plane with sides parallel to coordinate axes, without self-crossings and self-contacts. The broken line consists of K segments. You have to determine, whether a given point with coordinates (X₀,Y₀) is inside this closed broken line, outside or belongs to the broken line.

Input

The first line contains integer K (4 �K� 10000) - the number of broken line segments. Each of the following N lines contains coordinates of the beginning and end points of the segments (4 integer x_i1,y_i1,x_i2,y_i2; all numbers in a range from -10000 up to 10000 inclusive). Number separate by a space. The segments are given in random order. Last line contains 2 integers X₀ and Y₀- the coordinates of the given point delimited by a space. (Numbers X₀, Y₀in a range from -10000 up to 10000 inclusive).

Output

The first line should contain:

INSIDE - if the point is inside closed broken line,

OUTSIDE - if the point is outside,

BORDER - if the point belongs to broken line.

Sample Input

40 0 0 33 3 3 00 3 3 33 0 0 02 2

Sample Output

INSIDE

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Author: Alex Y. Suslov, Sergey V. MironovResource: 5th Southern Subregional Contest. Saratov 2002Date: 2002-10-10

题目大意

给出k条平行于x和y轴的线段，再给出一个点的坐标，问这个点是否在坐标内

思路：

看了一下如何判断点在多边形内部的博客。就是根据一点，往两边延伸，如果是都是偶数，那么就是外部，不然是在内部。然后如何这个点延伸出去的线和其中一个的端点有关，那么，我们就只加入这条线段的上端点，而不加入下端点。