归档 2014年10月16日

[Leetcode]Max Points on a Line

题目描述

Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.

题目大意

平面上有n个点,找出共线的点的最大个数

解题思路

很容易想到O(n^3)的解法,通过起点i,终点j枚举直线,然后枚举中间点k,依次判断k与i,j是否共线,统计最大值。

实际上,采用此题可以采用O(n^2 * log ...

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[Leetcode]Evaluate Reverse Polish Notation

题目描述

Evaluate the value of an arithmetic expression in Reverse Polish Notation.

Valid operators are +, -, *, /. Each operand may be an integer or another expression.

Some examples:
  ["2", "1", "+", "3", "*"] -> ((2 + 1) * 3) -> 9 ...

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[Leetcode]Reverse Words in a String

题目描述

Given an input string, reverse the string word by word.

For example,
Given s = "the sky is blue",
return "blue is sky the".

Clarification:

What constitutes a word?
A sequence of non-space characters constitutes a word.

Could the input ...

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