LeetCode Search a 2D Matrix

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.

For example,

Consider the following matrix:

[
  [1,   3,  5,  7],
  [10, 11, 16, 20],
  [23, 30, 34, 50]
]

Given target = 3, return true.

public class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
            int line=0;
        if (matrix.length<1) {
            return false;
        }
        if (target<matrix[0][0]) {
            return false;
        }
        for (int i = 1; i < matrix.length; i++) {
            if (matrix[i][0]>target) {
                line=i-1;
                break;
            }
            if (matrix[i][0]==target) {
                return true;
            }
        if (matrix[i][matrix[i].length-1]>=target) {
            line=i;
        }            
        }

        for (int is : matrix[line]) {
            if (is==target) {
                return true;
            }
        }
        return false;
    }
}