CF1147B.Chladni Figure
普及+/提高
通过率:0%
时间限制:3.00s
内存限制:256MB
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题目描述
Inaka has a disc, the circumference of which is n units. The circumference is equally divided by n points numbered clockwise from 1 to n, such that points i and i+1 (1≤i<n) are adjacent, and so are points n and 1.
There are m straight segments on the disc, the endpoints of which are all among the aforementioned n points.
Inaka wants to know if her image is rotationally symmetrical, i.e. if there is an integer k (1≤k<n), such that if all segments are rotated clockwise around the center of the circle by k units, the new image will be the same as the original one.
伊纳卡有一个圆盘,其周长为 n 个单位。该圆周被 n 个点等距划分,这些点按顺时针方向编号为 1 至 n,使得点 i 与点 i+1(其中 1≤i<n)相邻,且点 n 与点 1 也相邻。
圆盘上有 m 条直线段,每条线段的两个端点均来自上述 n 个点。
伊纳卡想知道她的图像是否具有旋转对称性,即:是否存在一个整数 k(满足 1≤k<n),使得将所有线段绕圆心顺时针旋转 k 个单位后,所得新图像与原图像完全相同。
输入格式
The first line contains two space-separated integers n and m (2≤n≤100000, 1≤m≤200000) — the number of points and the number of segments, respectively.
The i-th of the following m lines contains two space-separated integers ai and bi (1≤ai,bi≤n, ai=bi) that describe a segment connecting points ai and bi.
It is guaranteed that no segments coincide.
第一行包含两个用空格分隔的整数 n 和 m(2≤n≤100000,1≤m≤200000),分别表示点的数量和线段的数量。
接下来的 m 行中,第 i 行包含两个用空格分隔的整数 ai 和 bi(1≤ai,bi≤n,ai=bi),描述一条连接点 ai 和 bi 的线段。
保证不存在重合的线段。
输出格式
Output one line — "Yes" if the image is rotationally symmetrical, and "No" otherwise (both excluding quotation marks).
You can output each letter in any case (upper or lower).
输出一行——如果该图像具有旋转对称性,则输出“Yes”,否则输出“No”(均不包含引号)。
每个字母可以以任意大小写形式输出(大写或小写)。
输入输出样例
输入#1
12 6 1 3 3 7 5 7 7 11 9 11 11 3
输出#1
Yes
输入#2
9 6 4 5 5 6 7 8 8 9 1 2 2 3
输出#2
Yes
输入#3
10 3 1 2 3 2 7 2
输出#3
No
输入#4
10 2 1 6 2 7
输出#4
Yes
说明/提示
The first two examples are illustrated below. Both images become the same as their respective original ones after a clockwise rotation of 120 degrees around the center.

前两个示例在下方图示中给出。两张图片分别绕中心顺时针旋转 120 度后,均与各自的原始图像完全相同。

输入解题思路,AI测评打分。不知道怎么写?