13611361 SUSTech Online Judge
Problem 1361 --[Hard] Skylar's Magic Matrix

## 1361: [Hard] Skylar's Magic Matrix

Time Limit: 2 Sec  Memory Limit: 128 MB
Submit: 5  Solved: 2
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## Description

A matrix is magic, if the difference between its maxmium and mimimum elements ≤ $$m$$. Skylar has a large $$N*N$$ matrix $$M$$. She would like to know size of the biggest magic sub-matrix of $$M$$.

## Input

Input contains multiple test cases. The first line of input contains a single integer $$T (1 \leq T \leq 1000)$$. The number of test cases.

For each case, the first line contains two numbers $$N (1 \leq N \leq 500)$$ and $$M (0 \leq M \leq 100000)$$, representing the given matrix is $$N$$ square matrix and magic equilibrium value is $$M$$. Each of the next $$N$$ rows contains $$N$$ integers, representing the large matrix. Elements are positive integers and not larger than $$10^5$$. It is guaranteed that the sum of $$N^3$$ for all test cases is not exceed $$2\cdot 10^8$$.

## Output

For each case, print size of the biggest magic sub-matrix of $$M$$ in one line.

## Sample Input

2
2 0
3 3
2 3
3 1
2 4 3
3 4 2
4 3 2

## Sample Output

2
4

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