Hello I am trying to solve simple graph algorithms problem counting room. In this problem I am getting runtime and time limit exceeded if vector is not defined globally. Can someone tell why this is happening.

Problem link - Counting rooms

Accepted code - Accepted code TLE and RE showing code - Rejected code

My approach- I am calling dfs function for every unvisited cell and coloring the visited cell.
The number of times dfs is called will be the answer.

CodePudding user response：

In the Rejected code you are passing vector by value which is making copies of the the vector again and again.

CodePudding user response：

Pass vector by reference i.e. simply put '&' sign before vector in arguments of dfs function

CodePudding user response：

in the rejected code when you are calling the function it is making a new copy of the vector which takes o(size of(vector)), which is expensive instead of that u can define the vector as a global vector and use it further