Given any Binary Tree and any integer k $,$

i$.(5$ marks$)$ Write an algorithm "CountPaths" to count the number of paths from root to leaf that sum to k $.$

For the below Binary tree when the value of $k=5$ CountPaths will return $3,$ when the value of $k=2,$ CountPaths will return $0$ and for $k=6,$ CountPaths will return $0.$

ii$.(1$ mark$)$ Calculate the time complexity of the algorithm. $($Remember to include the number of operations per node$)$