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Abhishek Chaudhary
Abhishek Chaudhary

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Search a 2D Matrix

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:

class Solution:
    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
        m = len(matrix)
        n = len(matrix[0])
        beg = 0
        end = m * n - 1
        while beg <= end:
            mid = (beg + end) // 2
            i = mid // n
            j = mid % n
            if matrix[i][j] == target:
                return True
            elif beg == end:
                break
            elif matrix[i][j] < target:
                beg = mid + 1
            else:
                end = mid
        return False
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