#P7683. Aladdin's Golden Pear Quest
Aladdin's Golden Pear Quest
Aladdin's Golden Pear Quest
Aladdin is searching for the Golden Pear in a vast desert represented as an \(n\times n\) grid. The rows and columns are numbered from 1 to \(n\) (top‐to‐bottom and left‐to‐right respectively). In the desert there are \(m\) wizards, each positioned in a grid cell. Every wizard has a weekly schedule given by a string of 7 characters (each being L
, R
or S
) corresponding to the days Monday through Sunday. A character of L
means that on that day the wizard, if awake, instructs Aladdin to turn left (\(90^\circ\)); R
instructs him to turn right (\(90^\circ\)); and S
means the wizard is sleeping.
Aladdin starts his adventure on Monday at the top‐left cell, \((1, 1)\), and is initially facing right (east). Every day he repeats the following steps:
- If there is a wizard in his current cell and the wizard is awake (i.e. the schedule character for that day is
L
orR
), he turns accordingly. Turning left means a \(90^\circ\) turn counterclockwise and turning right means a \(90^\circ\) turn clockwise. - If moving forward in his current direction would take him out of the desert, he turns \(180^\circ\). This counts as an additional turn.
- Aladdin then moves one cell forward in his current direction, which takes one day.
An ancient prophecy foretells that immediately after Aladdin changes direction a total of \(k\) times (whether due to a wizard’s instruction or because he turns when facing the desert boundary), he will find the Golden Pear. Write a program to determine how many days Aladdin’s adventure lasts (i.e. the number of days completed before he finds the Golden Pear).
Note: If a turn that makes the total number of turns equal to \(k\) occurs during step 1 or step 2, the adventure ends immediately without completing the movement step of that day.
inputFormat
The first line contains three integers \(n\), \(m\), and \(k\) \((1 \leq n \leq 10^3, \; 0 \leq m \leq n^2, \; 1 \leq k \leq 10^6)\).
Then \(m\) lines follow. Each of these lines contains two integers \(r\) and \(c\) \((1 \leq r, c \leq n)\) and a string of 7 characters representing the wizard's weekly schedule starting from Monday. The characters in the schedule are all either L
, R
, or S
.
If a cell does not contain any wizard, no instruction is given in that cell.
outputFormat
Output a single integer representing the number of days Aladdin’s adventure lasts before he finds the Golden Pear.
sample
5 1 1
1 1 RRSRRSS
0