Search Matrix 2

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 in ascending from left to right. Integers in each column are sorted in ascending from top to bottom. For example,

Consider the following matrix:

[
  [1,   4,  7, 11, 15],
  [2,   5,  8, 12, 19],
  [3,   6,  9, 16, 22],
  [10, 13, 14, 17, 24],
  [18, 21, 23, 26, 30]
]

Given target = 5, return true.

Given target = 20, return false.

Solution

class Solution(object):
    def searchMatrix(self, matrix, target):
        """
        :type matrix: List[List[int]]
        :type target: int
        :rtype: bool
        """
        m, n,  = len(matrix), len(matrix[0])
        r, c = 0, n - 1
        while r < m and c >= 0:
            if matrix[r][c] == target:
                return True
            if matrix[r][c] > target:
                c -= 1
            else:
                r += 1
        return False

public class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        if(matrix == null || matrix.length < 1 || matrix[0].length <1) {
            return false;
        }

        int row = 0, col = matrix[0].length - 1;

        while(col >= 0 && row < matrix.length) {
            if(target == matrix[row][col])
                return true;
            else if(target > matrix[row][col])
                row++;
            else
                col--;
        }

        return false;
    }
}