When I am about to know some algorithms I confused about what exacly is input size.
For example in travelling sales person problem dynamic programming implementation takes O(2n × n2)
And krushals algorithm takes
O(E log V).Though both are graph problems why TSP input size is no.of Vertices n and krushals input size is in Edges and Vertices.
How to know exactly what can be taken as input size
You can state an algorithm’s complexity in terms of whatever variables you like.
You should generally choose them to clearly communicate useful information about the running time of the algorithm.