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Evaluate Reverse Polish NotationYou are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation.Evaluate the expression. Return an integer that represents the value of the expression.Note that:The valid operators are '+', '-', '*', and '/'.Each operand may be an integer or another expression.The division between two integers always truncates toward ..

Path SumGiven the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.A leaf is a node with no children. Example 1:Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22Output: trueExplanation: The root-to-leaf path with the target sum is shown.Example 2:Input: root = [..