Simple Arithmetic Parser with Constant Space

Description Given a string representing a simple mathematical expression containing only addition (+) and multiplication (*) operators, write a function to evaluate the value of the expression. The evaluation should be done using constant space complexity without using a stack. Input A string expr with a maximum length of 100, containing only digits and operators + and *. Output An integer representing the evaluated value. Example Input: "3+5*2" Output: 13 Input: "2*3+4" Output: 10 Constraints The expression will not be empty. There will be no spaces between '+' and '*' operators. Example Input "3+5*2"