CF556B.Case of Fake Numbers
普及/提高-
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题目描述
Andrewid the Android is a galaxy-famous detective. He is now investigating a case of frauds who make fake copies of the famous Stolp's gears, puzzles that are as famous as the Rubik's cube once was.
Its most important components are a button and a line of n similar gears. Each gear has n teeth containing all numbers from 0 to n−1 in the counter-clockwise order. When you push a button, the first gear rotates clockwise, then the second gear rotates counter-clockwise, the the third gear rotates clockwise an so on.
Besides, each gear has exactly one active tooth. When a gear turns, a new active tooth is the one following after the current active tooth according to the direction of the rotation. For example, if n=5 , and the active tooth is the one containing number 0 , then clockwise rotation makes the tooth with number 1 active, or the counter-clockwise rotating makes the tooth number 4 active.
Andrewid remembers that the real puzzle has the following property: you can push the button multiple times in such a way that in the end the numbers on the active teeth of the gears from first to last form sequence 0,1,2,...,n−1 . Write a program that determines whether the given puzzle is real or fake.
输入格式
The first line contains integer n ( 1<=n<=1000 ) — the number of gears.
The second line contains n digits a1,a2,...,an ( 0<=ai<=n−1 ) — the sequence of active teeth: the active tooth of the i -th gear contains number ai .
输出格式
In a single line print "Yes" (without the quotes), if the given Stolp's gears puzzle is real, and "No" (without the quotes) otherwise.
输入输出样例
输入#1
3 1 0 0
输出#1
Yes
输入#2
5 4 2 1 4 3
输出#2
Yes
输入#3
4 0 2 3 1
输出#3
No
说明/提示
In the first sample test when you push the button for the first time, the sequence of active teeth will be 2 2 1, when you push it for the second time, you get 0 1 2.