leetcode.com/explore/featured/card/top-interview-questions-easy/94/trees/555/ Explore - LeetCode LeetCode Explore is the best place for everyone to start practicing and learning on LeetCode. No matter if you are a beginner or a master, there are always new topics waiting for you to explore. leetcode.com root 가 null 이면 return 0 하고, leaf 노드이면 1을 리턴하면 되지 않을까..해서 어쨋든 루트 노드에 닿아야 한다고 생각했던 나는 루트 노드의 개수..