Given an m x n matrix mat, return an array of all the elements of the array in a diagonal order.
Example 1:
Input: mat = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,2,4,7,5,3,6,8,9]
Example 2:
Input: mat = [[1,2],[3,4]]
Output: [1,2,3,4]
Constraints:
-
m == mat.length -
n == mat[i].length -
1 <= m, n <= 104 -
1 <= m * n <= 104 -
-105 <= mat[i][j] <= 105
SOLUTION:
class Solution:
def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
m = len(mat)
n = len(mat[0])
op = []
x, y = 0, 0
while len(op) != m * n:
slope = (x + y) & 1
op.append(mat[y][x])
dx, dy = (-1, 1) if slope else (1, -1)
if x + dx < 0 or x + dx >= n or y + dy < 0 or y + dy >= m:
if slope:
if y < m - 1:
y += 1
else:
x += 1
else:
if x < n - 1:
x += 1
else:
y += 1
else:
x += dx
y += dy
return op
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