题目描述
Problem Statement
There is a grid with N rows and N columns. We denote by (i, j) the square at the $i-th (1 \leq i \leq N)$ row from the top and $j-th (1 \leq j \leq N)$ column from the left.
Square (i, j) has a non-negative integer a_{i, j} written on it.
When you are at square (i, j), you can move to either square (i+1, j) or (i, j+1). Here, you are not allowed to go outside the grid.
Find the number of ways to travel from square (1, 1) to square (N, N) such that the exclusive logical sum of the integers written on the squares visited (including (1, 1) and (N, N)) is 0.
What is the exclusive logical sum?
The exclusive logical sum $a \oplus b$ of two integers a and b is defined as follows.
-
The 2^k'$s place (k \geq 0)$ in the binary notation of $a \oplus b$ is 1 if exactly one of the 2^k's places in the binary notation of a and b is 1; otherwise, it is 0.
For example$, 3 \oplus 5 = 6$ (In binary notation: $011 \oplus 101 = 110)$.
In general, the exclusive logical sum of $k integers p_1, \dots, p_k$ is defined as $(\cdots ((p_1 \oplus p_2) \oplus p_3) \oplus \cdots \oplus p_k)$. We can prove that it is independent of the order of $p_1, \dots, p_k$.
Input
The input is given from Standard Input in the following format:
N
$a_{1, 1} \ldots a_{1, N}$
$\vdots$
$a_{N, 1} \ldots a_{N, N}$
Output
Print the answer.
Constraints
- $2 \leq N \leq 20$
- $0 \leq a_{i, j} \lt 2^{30}$ $, (1 \leq i, j \leq N)$
- All values in the input are integers.
Sample Input 1
3
1 5 2
7 0 5
4 2 3
Sample Output 1
2
The following two ways satisfy the condition:
- $(1, 1) \rightarrow (1, 2) \rightarrow (1, 3) \rightarrow (2, 3) \rightarrow (3, 3)$;
- $(1, 1) \rightarrow (2, 1) \rightarrow (2, 2) \rightarrow (2, 3) \rightarrow (3, 3)$.
Sample Input 2
2
1 2
2 1
Sample Output 2
0
Sample Input 3
10
1 0 1 0 0 1 0 0 0 1
0 0 0 1 0 1 0 1 1 0
1 0 0 0 1 0 1 0 0 0
0 1 0 0 0 1 1 0 0 1
0 0 1 1 0 1 1 0 1 0
1 0 0 0 1 0 0 1 1 0
1 1 1 0 0 0 1 1 0 0
0 1 1 0 0 1 1 0 1 0
1 0 1 1 0 0 0 0 0 0
1 0 1 1 0 0 1 1 1 0
Sample Output 3
24307
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分