For this Problem

1829E - The Lakes

The solution is written in O(n*m)

But How it is possible if there is recursion calls inside the nested solution.

Solution in tutorial is:

https://codeforces.net/blog/entry/116108 (Problem E)

Please someone help me understand the time complexity?Shouldn't it be O(n*m*n*m).I know we are not checking same grid twice.

Please someone help me.