题目描述
Problem Statement
Snuke is playing a puzzle game.
In this game, you are given a rectangular board of dimensions R × C, filled with numbers. Each integer i from 1 through N is written twice, at the coordinates (x_{i,1},y_{i,1}) and (x_{i,2},y_{i,2}).
The objective is to draw a curve connecting the pair of points where the same integer is written, for every integer from 1 through N.
Here, the curves may not go outside the board or cross each other.
Determine whether this is possible.
Input
Input is given from Standard Input in the following format:
R C N
x_{1,1} y_{1,1} x_{1,2} y_{1,2}
:
x_{N,1} y_{N,1} x_{N,2} y_{N,2}
Output
Print YES if the objective is achievable; print NO otherwise.
Constraints
- 1 ≤ R,C ≤ 10^8
- 1 ≤ N ≤ 10^5
- 0 ≤ x_{i,1},x_{i,2} ≤ R(1 ≤ i ≤ N)
- 0 ≤ y_{i,1},y_{i,2} ≤ C(1 ≤ i ≤ N)
- All given points are distinct.
- All input values are integers.
Sample Input 1
4 2 3
0 1 3 1
1 1 4 1
2 0 2 2
Sample Output 1
YES
The above figure shows a possible solution.
Sample Input 2
2 2 4
0 0 2 2
2 0 0 1
0 2 1 2
1 1 2 1
Sample Output 2
NO
Sample Input 3
5 5 7
0 0 2 4
2 3 4 5
3 5 5 2
5 5 5 4
0 3 5 1
2 2 4 4
0 5 4 1
Sample Output 3
YES
Sample Input 4
1 1 2
0 0 1 1
1 0 0 1
Sample Output 4
NO
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分