#P3194. [HNOI2008] 水平可见直线
[HNOI2008] 水平可见直线
Description
On the Cartesian coordinate plane, there are lines . If, when looking downward from , some subsegment of is visible, we say that is visible; otherwise, is covered. For example, for the lines: ; ; ; then and are visible, and is covered. Given lines in the form (), and no two lines coincide, find all visible lines.
Input Format
The first line contains (). The next lines each contain .
Output Format
Output the indices of the visible lines in increasing order, separated by spaces. There must also be a space after the last number.
3
-1 0
1 0
0 0
1 2
Hint
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