从矩阵中查找一个数

/**
 * Created by seven_hu on 2015/8/31.
 */
/*
* 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.
*
*
*/
public class Search2DMatrix {
    public static void main(String[] args){
        int[][] 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}
        };
        boolean result=searchIntIn2DMatrix(matrix,5);
        System.out.println(result);
    }
    public static boolean searchIntIn2DMatrix(int[][] matrix, int target) {
        if(matrix == null || matrix.length < 1 || matrix[0].length <1) {
            return false;
        }
        int col = matrix[0].length-1;
        int row = 0;
        while(col >= 0 && row <= matrix.length-1) {
            if(target == matrix[row][col]) {
                return true;
            } else if(target < matrix[row][col]) {
                col--;
            } else if(target > matrix[row][col]) {
                row++;
            }
        }
        return false;
    }

}