題目來源:judgegirl from ntu prof. pangfeng Liu
Task Description
This exercise 6.10 in the textbook.
We have a room with a lot of mirrors. The rectangular room is of size by . You can think of the room consists of square cells, each is of unit length. Within each cell we may place a mirror. The mirror is two sided so that both sides reflect light. Now there are windows around the room, each is centered at one of boundary cells, Like in the following figure. If we stand at window 0 and look into the room, we will see the person standing at window 8. Now write a program that, given the position of these windows, calculates the windows number we would be able to see if we stand at a particular window.
Input
The first line of the input has two numbers, and , representing the width and the depth of the room. Both and are positive integers and no more than 100. Each of the next lines has numbers, with 1 representing a mirror, and 0 for no mirror. The numbers are from top to bottom, left to right.
Output
The output has lines, and each line has one number. The number in the -th line indicates the window number that can be seen from the -th window.
Sample input
5 4
0 1 0 1 0
0 0 1 0 0
1 0 0 1 1
0 1 1 0 0
Sample output
8
7
5
9
6
2
4
1
0
3
17
15
14
16
12
11
13
10