Android开发中，有时候根据需求要隐藏标题栏、状态栏、导航栏或者全屏显示。看似很简单的功能，但是不注意使用环境，就会出现错误。
java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
在AndroidManifest.xml中使用
android:theme="@android:style/Theme.Light.NoTitl......
Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1.
Example
Example 1:
Input: 123
Output: "One Hundred Twenty Three"
Example 2:
Input: 12345
Output: "Twelve Thousand Three Hundred Forty Five"
Example 3:
Input: 1234567
Output: "One Million Two Hundred Thirty Four Thousand Five Hundr......
Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.
Symbol
Value
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, which is simply X + II. The number twenty seven is written as XXVII, which is XX + V ......
Description
On an 8 x 8 chessboard, there is one white rook. There also may be empty squares, white bishops, and black pawns. These are given as characters 'R', '.', 'B', and 'p' respectively. Uppercase characters represent white pieces, and lowercase characters represent black pieces.
The rook moves as in the rules of Chess: it chooses one of four cardinal direction......
Given an array of integers arr and an integer k. Find the least number of unique integers after removing exactly k elements.
Example 1:
Input: arr = [5,5,4], k = 1
Output: 1
Explanation: Remove the single 4, only 5 is left.
Example 2:
Input: arr = [4,3,1,1,3,3,2], k = 3
Output: 2
Explanation: Remove 4, 2 and either one o......
