Leetcode 199. Binary Tree Right Side View (DFS/BFS好题)
BinaryTreeRightSideViewMediumGiventherootofabinarytree,imagineyourselfstandingontherightsideofit,returnthevaluesofthenodesyoucanseeorderedfromtoptobottom.Example1:Input:root=[1,2,3,null,5,null,4]Outpu