大鱼的博客

题目描述: Given a pattern and a string str, find if str follows the same pattern.   Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in st...

题目描述： Implement int sqrt(int x). Compute and return the square root of x, where x is guaranteed to be a non-negative integer. Since the return type is an integer, the decimal digits are truncate...

题目描述： Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Ou...

题目： Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type...

  题目描述: A robot on an infinite grid starts at point (0, 0) and faces north. The robot can receive one of three possible types of commands: -2: turn left 90 degrees -1: turn right 90 degrees 1 &lt...

题目描述： The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) P A H N A P ...