题意：就是判断各线段之间有没有交点。
判断两线段相交，要运用到叉积。两个线段相交肯定相互跨越，假设一个条线段（p1p2），另一条是（q1q2），那么p1p2肯定在q1q2线段的两侧，那么运用叉积如果p1p2跨越q1q2的话（q1p1）x（q2p2）《= 0.同样也要验证 q1q2是不是也跨越p1p2，注意：p1p2跨越q1q2，不代两个线段相交，可能是p1p2跨越直线q1q2，所以说还是要再次判断q1q2是不是跨越p1p2
还有另外一种比较容易理解的解法：
就是如果两个线段相交，那么两线段两端端点的差即（p...
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其他好文 时间：
2014-08-21 09:51:13
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Cina. The other type of bucket trucks that is also widely used is the Elevating Work Platforms or most commonly known as scissor lift is one type of p...
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2014-08-21 09:43:53
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Description
Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if there are no integers x > 1, y > 0, z > 0 such ...
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2014-08-20 22:41:13
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Description
Problem E: How many 0's?
A Benedict monk No. 16 writes down the decimal representations of all natural numbers between and including
m and n, m ≤ n. How many 0's will he write down?
...
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其他好文 时间：
2014-08-20 19:42:02
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Kindergarten Counting Game
Everybody sit down in a circle. Ok. Listen to me carefully.
``Woooooo, you scwewy wabbit!''
Now, could someone tell me how many words I just said?
Input and...
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2014-08-20 18:04:02
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A squarenumber is an integer number whose square root is also an integer. For example1, 4, 81 are some square numbers. Given two numbers a and b you will have tofind out how many square numbers are th...
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2014-08-20 16:28:22
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2014-08-20 10:46:22,356 INFO [coreZkRegister-1-thread-1] [org.apache.solr.cloud.ShardLeaderElectionContext] - Was waiting for replicas to come up, but they are taking too long - assuming they won't c...
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2014-08-20 12:36:22
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Problem:
s0 = "a", s1 = "b", s2 = "ba", s3 = "bab", s4 = "babba", s4 = "babbabab", is called Fibonacci string. For the string with index n, given a string str = "bb", calculate how many times in the...
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2014-08-20 12:31:22
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[root@athController~]#novalistERROR:Anunexpectederrorpreventedtheserverfromfulfillingyourrequest.(OperationalError)(1040,‘Toomanyconnections‘)NoneNone(HTTP500)解决办法：key_buffer=64Mmax_allowed_packet=16Mthread_stack=192Kthread_cache_size=8myisam-recover=B..
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数据库 时间：
2014-08-20 10:35:46
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437
题目：Given an integer N, and how many pairs (A;B) are there such that: gcd(A;B) = A xor B where 1=2)是不同位数的。和同学讨论后得出如下证明：设最大公约数为 j, 假设这两个数是b 和 b+k*j，（k>....
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2014-08-19 23:50:55
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