
There is a strange printer with the following two special requirements:
On each turn, the printer will print a solid rectangular pattern of a single color on the grid. This will cover up the existing colors in the rectangle.
Once the printer has used a color for the above operation, the same color cannot be used again .
You are given a m x n matrix targetGrid , where targetGrid[row][col] is the color in the position (row, col) of the grid.
Return true if it is possible to print the matrix targetGrid , otherwise, return false .
m == targetGrid.lengthn == targetGrid[i].length1 <= m, n <= 601 <= targetGrid[row][col] <= 60