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