Search a 2D matrix 2.java

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