摘要：
Determine whether an integer is a palindrome. Do this without extra space.Some hints:Could negative integers be palindromes? (ie, -1)If you are thinki... 阅读全文
摘要：
Given a binary tree, find the maximum path sum.The path may start and end at any node in the tree.For example:Given the below binary tree, 1 ... 阅读全文
摘要：
Givennpoints on a 2D plane, find the maximum number of points that lie on the same straight line.题解：思路比较简单，每条直线都可以表示为y=kx+b，所以对于任意三点，如果它们共线，那么它们中任意两点的... 阅读全文