Rotate Image
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise). [#48]
Note:
You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
Example 1: Given input matrix = [ [1,2,3], [4,5,6], [7,8,9] ], rotate the input matrix in-place such that it becomes: [ [7,4,1], [8,5,2], [9,6,3] ] Example 2: Given input matrix = [ [ 5, 1, 9,11], [ 2, 4, 8,10], [13, 3, 6, 7], [15,14,12,16] ], rotate the input matrix in-place such that it becomes: [ [15,13, 2, 5], [14, 3, 4, 1], [12, 6, 8, 9], [16, 7,10,11] ]
Group Anagrams
Given an array of strings, group anagrams together. [#49]
Example: Input: ["eat", "tea", "tan", "ate", "nat", "bat"], Output: [ ["ate","eat","tea"], ["nat","tan"], ["bat"] ]
Note:
All inputs will be in lowercase.
The order of your output does not matter.
Pow(x, n)
Implement pow(x, n), which calculates x raised to the power n (xn). [#50]
Examples: Input: 2.00000, 10 Output: 1024.00000 Input: 2.10000, 3 Output: 9.26100 Input: 2.00000, -2 Output: 0.25000 Explanation: 2^-2 = (1/2)^2 = 1/4 = 0.25
Note:
-100.0 < x < 100.0 n is a 32-bit signed integer, within the range [−2^31, 2^31− 1]
