【Leetcode】Search a 2D Matrix in JAVA

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

.

这道题很简单就不多说了，就是通过每一行的首数字大小先判断在哪一行，然后在某一行里搜索。其实如果高效的话应该在每一行里还做二分搜索，我就犯懒了。。反正也过了

public class Search2DMatrix {
public static void main(String args[]){
Search2DMatrix sm = new Search2DMatrix();
int[][] put = {{1,   3,  5,  7},
{10, 11, 16, 20},
{23, 30, 34, 50}};
System.out.println(sm.searchMatrix(put, 12));
}
public boolean searchMatrix(int[][] matrix, int target) {
int i=0;
while(i<matrix.length-1){
if(target>=matrix[i][0]&&target<matrix[i+1][0]){
for(int j=0;j<matrix[i].length;j++)
if(matrix[i][j]==target)	return true;
}
i++;
}
for(int j=0;j<matrix[matrix.length-1].length;j++){
if(matrix[matrix.length-1][j]==target)	return true;
}
return false;
}
}