Why is True not being returned to the "exist" main func when the first if statement in dfs is being hit? I'm sure I'm just missing something simple.
Leetcode question: https://leetcode.com/explore/interview/card/top-interview-questions-medium/109/backtracking/797/
class Solution:
def exist(self, board: List[List[str]], word: str) -> bool:
def dfs(x=0, y=0, found=0, seen = set()):
if found == len(word):
return True
elif x < len(board) and y < len(board[0]) and board[x][y] == word[found]:
if x > 0 and (x,y) not in seen:
seen.add((x,y))
dfs(x-1,y,found+1, seen.copy())
seen.remove((x,y))
if x < len(board) and (x,y) not in seen:
seen.add((x,y))
dfs(x+1,y,found+1, seen.copy())
seen.remove((x,y))
if y > 0 and (x,y) not in seen:
seen.add((x,y))
dfs(x,y-1,found+1, seen.copy())
seen.remove((x,y))
if y < len(board[0]) and (x,y) not in seen:
seen.add((x,y))
dfs(x,y+1,found+1, seen.copy())
seen.remove((x,y))
return dfs()
