class Solution:
   def solve(self, matrix):
      R = len(matrix)
      C = len(matrix[0])

      def get_neighbors(i, j):
                  val = matrix[i][j]
         for ii, jj in ((i + 1, j), (i - 1, j), (i, j + 1), (i, j - 1)):
            if 0 <= ii < R and 0 <= jj < C and matrix[ii][jj] == val:
               yield ii, jj

      vis = [[False] * C for _ in range(R)]

      def dfs(root):
         stack = [(root, None)]
         vis[root[0]][root[1]] = True
         while stack:
            v, prev = stack.pop()
            for w in get_neighbors(*v):
               if w != prev:
                  if not vis[w[0]][w[1]]:
                     vis[w[0]][w[1]] = True
                     stack.append((w, v))
                  else:
                     return True
         return False

      for i in range(R):
         for j in range(C):
            if not vis[i][j]:
               if dfs((i, j)):
                  return True
      return False
     
ob = Solution()
matrix = [
   [2, 2, 2, 1],
   [2, 1, 2, 1],
   [2, 2, 2, 1]
]
print(ob.solve(matrix))

[  
[2, 2, 2, 1],  
[2, 1, 2, 1],  
[2, 2, 2, 1] ]

True