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There are K line segments on a plane. These are all segments of a broken line, in arbitrary order. Write a program to check whether the broken line is closed.
Input data is in (4*K+1) lines, each of them consists of no more then 250 characters. The first line of the file contains the number of segments K (1≤K≤3000). Each segment is described by the coordinates X’, Y’, X’’, and Y’’ of its end-points. All coordinates are non-negatives integers and written in separate lines (so, the coordinates of one segment are in four sequential lines).
The first and only line of the file must contain the number 1 if the broken line is closed, and 0 otherwise.
3 0 0 0 1 1 0 0 0 1 0 0 1
1
| 时间上限 | 内存上限 |
| 1000 | 65536 |