1591 - Strange Printer II\.

Hard

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.

Example 1:

Input: targetGrid = \[\[1,1,1,1],1,2,2,1,1,2,2,1,1,1,1,1]

Output: true

Example 2:

Input: targetGrid = \[\[1,1,1,1],1,1,3,3,1,1,3,4,5,5,1,4]

Output: true

Example 3:

Input: targetGrid = \[\[1,2,1],2,1,2,1,2,1]

Output: false

Explanation: It is impossible to form targetGrid because it is not allowed to print the same color in different turns.

Constraints:

• m == targetGrid.length

• n == targetGrid[i].length

• 1 <= m, n <= 60

• 1 <= targetGrid[row][col] <= 60