Evaluate an Arithmetic Expression

Given a string expr representing an arithmetic expression, evaluate it. Rules expr contains non-negative integers, operators + - * /, parentheses ( ), and spaces. Operator precedence: * and / have higher precedence than + and -. Parentheses may override precedence. Division is integer division truncated toward zero (e.g., 7/3 = 2, -7/3 = -2). Return the evaluated result (fits in 32-bit signed integer). Examples Input: "3+2*2" Output: 7 Input: " (1+(4+5+2)-3) + (6+8) " Output: 23 Constraints (typical interview setting) 1 <= len(expr) <= 1e5 Test cases Example Input 3+2*2 Output 7