'''

public class SearchNumIn2DMatrix {

```
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}
};
System.out.println("5 exists? " + searchMatrix(matrix, 5));
System.out.println("20 exists? " + searchMatrix(matrix, 20));
}
public static boolean searchMatrix(int[][] matrix, int target) {
if(matrix.length ==0) return false;
int m=matrix.length-1;
int n=matrix[0].length-1;
int i=m;
int j=0;
while(i>=0 && j<=n){
if(target < matrix[i][j]){
i--;
}else if(target > matrix[i][j]){
j++;
}else{
return true;
}
}
return false;
}
}
```

'''