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Robi Kaka's Cube

By Mehedi_Hassan · Limits 1s, 512 MB

Our beloved Robi Kaka has invented a cube. You have to solve only one side of this cube – a square of N×NN\times N cells. Every cell has 44 colors – Red, Blue, Green, Yellow stripes drawn in clockwise direction one after another. There is also a white rotating button in the middle of each cell. Tapping it once rotates the cell 90°90° in clockwise direction.

We define the current state of a cell with its top color. Here are the four possible states of a cell, named after their top color

You are given a jumbled square. Robi kaka calls it solved only if every adjacent cell of it shares same color.

Being the most talented bhatija, Robi kaka will ask you QQ queries. Every time Robi kaka will select cell (i,j)(i, j) and press the white button exactly once. Then Robi kaka asks you to find the minimum number of rotations (using the white button) needed to solve the square. Every rotation made by Robi kaka takes place.

Note that, to answer each query, you just take a look at the cube and answer the minimum number of rotation required. But you do not perform any operation on the cube.


The first line contains an integer TT (1T5)\left(1 \leq T \leq 5\right), number of test cases.

For each test case the first line contains an integer NN (1N500)\left(1 \leq N \leq 500\right), length of the side of the square.

The following NN lines each contain a string of NN characters, denoting the initial square. The character in the ii-th row and jj-th column is one of 'R\texttt{R}', 'Y\texttt{Y}', 'G\texttt{G}', 'B\texttt{B}' denoting the top color of the cell in the ii-th row from top and jj-th column from left of the square.

The next line will contain an integer QQ (1Q105)\left(1 \leq Q \leq 10^5\right), the number of queries Robi Kaka will ask you.

The following QQ lines each contain 22 numbers, ii and jj (1i,jN)\left(1 \leq i, j \leq N\right), meaning that Robi Kaka rotates the cell in ii-th row from top and jj-th column from left using the button in it.


For each QQ query, print the minimum number of rotations needed to solve the square.


3 1
2 2



86% Solution Ratio

akash740Earliest, 1M ago

akash740Fastest, 0.1s

RakibJoyLightest, 3.8 MB

tahsin_protikShortest, 1549B


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There are only 4 possible Solved structure/formation. Now, let's calculate and store the number of ...