※ 引述《Leon (Achilles)》之銘言：
: : 接著說明一下直線截成線段的問題。
: : 對偶的時候，點(a,b)對偶成直線y=ax+b。
: : 考慮兩個直線的交點，也就是兩條直線解聯立方程式。
: : 根據公式解，交點的座標範圍一定會在 |a|*|b|+|c|*|d| 之內。
:
: First, I don't understant your notation.
: What do you mean by the range |a|*|b|+|c|*|d| ?
:
: It seems not a range in 2D ?
:
:
: And I have the same question for you.
:
: Assume you have N lines, based on your description
: You claim there is a range for the intersection.
:
: Then, how many operations you need to calculate the range?
:
:
:

恩 你說的沒錯 那麼範圍最大到 |d|+|b| 才對

you are wrong again, look, there is (a-c) term!

恩 你說的沒錯　除非abcd都是整數　範圍才是 |d|+|b|

then revise your post. Everyone should be responsible towhat they write

這是當然 XD

OK, your first statement is wrong. Now you can answerthe second question: