Skip to content

74. Search a 2D Matrix

Difficulty Topics

Description

Write an efficient algorithm that searches for a value target in an m x n integer matrix 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],[23,30,34,60]], target = 3
Output: true

Example 2:

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

 

Constraints:

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

Solution

search-a-2d-matrix.py
class Solution:
    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
        rows, cols = len(matrix), len(matrix[0])

        left, right = 0, rows * cols - 1

        while left <= right:
            mid = left + (right - left) // 2

            r, c = divmod(mid, cols)

            if matrix[r][c] == target:
                return True
            elif matrix[r][c] > target:
                right = mid - 1
            else:
                left = mid + 1

        return False