COJ - Traversing Grid 遍历格子的有关问题 题解
COJ - Traversing Grid 遍历格子的问题 题解
很有趣的题目：在一个方格上从最左上角面向右出发，每次行走一个，碰到边右走，或者碰到已经访问过的格子右转，问最后遍历所有格子的时候你是面向那个方向？
For example: Consider the case with N = 3, M = 3. The path followed will be (0,0) -> (0,1) -> (0,2) -> (1,2) -> (2,2) -> (2,1) -> (2,0) -> (1,0) -> (1,1). At this point, all squares
have been visited, and you are facing right.
Input specification
The first line contains T the number of test cases. Each of the next T lines contain two integers N and M,
denoting the number of rows and columns respectively.
Output specification
Output T lines, one for each test case, containing the required direction you will be facing at the end. Output L for left, R for right, U for up, and D for down. 1 <= T <= 5000, 1 <= N,M <= 10^9.
Sample input
4 1 1 2 2 3 1 3 3
Sample output
R L D R
一看题目好像很大的数据很难计算，不过其实是有规律的，并不用真的遍历所有格子。所以挺有趣的。
找出规律，几行代码就能通过了：
void TraversingGrid()
{
int n = 0, m = 0, T = 0;
cin>>T;
while (T--)
{
cin>>n>>m;
if (n <= m)
{
if (n % 2) cout<<'R'<<endl;
else cout<<'L'<<endl;
}
else
{
if (m % 2) cout<<'D'<<endl;
else cout<<'U'<<endl;
}
}
}
出处：
http://coj.uci.cu/24h/problem.xhtml?abb=1004