Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
Integers in each row are sorted from left to right.
The first integer of each row is greater than the last integer of the previous row.
Example 1:
Input:
matrix = [
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
target = 3
Output: true
Example 2:
Input:
matrix = [
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
target = 13
Output: false
class Solution:
def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
if not matrix or not matrix[0]:
return False
rl, rr = 0, len(matrix) - 1
cl, cr = 0, len(matrix[0]) - 1
while rl <= rr:
mid = (rl + rr) // 2
if target < matrix[mid][0]:
rr = mid - 1
elif target > matrix[mid][-1]:
rl = mid + 1
else:
rl = mid
break
if rl > rr:
return False
while cl <= cr:
mid = (cl + cr) // 2
if target < matrix[rl][mid]:
cr = mid - 1
elif target > matrix[rl][mid]:
cl = mid + 1
else:
return True
return False