update

[K]graph/[K]graph-dfs/329-longest-increasing-path-in-a-matrix.py

@@ -1,25 +1,25 @@
 class Solution:
  def longestIncreasingPath(self, matrix: List[List[int]]) -> int:
- res = 0
  rows, cols = len(matrix), len(matrix[0])
- counts = [[- 1 for _ in range(cols)] for _ in range(rows)]
+ cell_len = {}
 
  def dfs(r, c):
- next_count = 0
+ total = 1
+ new_total = total
  for next_r, next_c in [(r+1, c), (r-1, c), (r, c+1), (r, c-1)]:
  if next_r not in range(rows) or next_c not in range(cols) or matrix[r][c] >= matrix[next_r][next_c]:
  continue
- if counts[next_r][next_c] == - 1:
- next_count = max(next_count, dfs(next_r, next_c))
+ if (next_r, next_c) in cell_len:
+ new_total = max(new_total, total + cell_len[(next_r, next_c)])
  else:
- next_count = max(next_count, counts[next_r][next_c])
- counts[r][c] = 1 + next_count
- return counts[r][c]
- 
+ new_total = max(new_total, total + dfs(next_r, next_c))
+ cell_len[(r, c)] = new_total
+ return new_total
+
  for r in range(rows):
  for c in range(cols):
- res = max(res, dfs(r, c))
- return res
+ dfs(r, c)
+ return max(cell_len.values())
 
 # time O(RC)
 # space O(RC)