Given a string path, where path[i] = 'N', 'S', 'E' or 'W', each representing moving one unit north, south, east, or west, respectively. You start at the origin (0, 0) on a 2D plane and walk on the path specified by path.
Return true if the path crosses itself at any point, that is, if at any time you are on a location you have previously visited. Return false otherwise.
Example 1:
Input: path = "NES"
Output: false
Explanation: Notice that the path doesn't cross any point more than once.
Example 2:
Input: path = "NESWW"
Output: true
Explanation: Notice that the path visits the origin twice.
Solution
class Solution:
def isPathCrossing(self, path: str) -> bool:
seen = set()
seen.add((0,0))
x = 0
y = 0
for i in path:
if i == 'N':
y += 1
elif i == 'S':
y -= 1
elif i == 'W':
x += 1
elif i == 'E':
x -= 1
if (x, y) in seen:
return True
seen.add((x,y))
return False