Python describe LeetCode 74. Search for a two-dimensional matrix

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subject

Write an efficient algorithm to judge m x n Matrix , Is there a target value . The matrix has the following characteristics ：

• The integers in each row are arranged in ascending order from left to right .
• The first integer in each row is greater than the last integer in the previous row .

Example 1：

 Input ：matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3
Output ：true

Example 2：

 Input ：matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13
Output ：false

Tips ：

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 100
• -104 <= matrix[i][j], target <= 104

Python describe

The first two branches , Second breakdown

class Solution:
def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
n,m = len(matrix),len(matrix[0])
l,r = 0,n-1
while l < r:
mid = l + r + 1>> 1
if matrix[mid][0] == target:
return True
if matrix[mid][0] < target:
l = mid
else:
r = mid - 1
line = l
l,r = 0,m-1
while l < r:
mid = l + r >> 1
if matrix[line][mid] >= target:
r = mid
else:
l = mid + 1
return matrix[line][l] == target