00:01
You're given the grammar and semantic rules, the input sequence is begin east, south, west, north.
00:13
So begin to s to b to s .x, which is zero, and s .y.
00:21
And then you process each direction on eye in order.
00:27
So for east, that direction is 1, and idy would be 0.
00:40
For south, so, well, i guess before i do that, so s.
01:00
That x would be 0 plus 1, which is 1, and s.
01:03
Dot y is 0 plus 0, which is 0.
01:10
So, s that 1, or s1 .x is 1, s1 .y is 0, s1 .y is 0 plus 0 or 1.
01:28
And s.
01:29
Y is 0 plus negative 1, which is negative 1...