Problem 1: Given a graph G (V,E) a subset U S V of nodes is called a node cover if each edge in E is adjacent to at least one node in U. Given a graph, we do not know how to find the minimum node cover in an efficient manner. But if we restriet G to be a tree, then it is possible. Give a greedy algorithm that finds the minimum node cover for a tree. Analyze its correctness and running time. A tree if a connected graph with no cycles, i.e. where any pair of nodes is connected by a simple path