Evaluate Reverse Polish Notation — Level 8

At the Galactic Colosseum of Code, warriors from across the universe gather to compete in the legendary Quantum Coder tournament. The announcer's voice booms across the arena as the next bout is announced: "Evaluate Reverse Polish Notation — Level 8". The crowd roars, and the challenger steps into the ring. The opponent is not a living being but a puzzle of pure logic. The challenger must solve it faster and more accurately than the clock allows. Victory means glory across the stars; defeat means humiliation before billions. Read a space-separated string of tokens (integers and operators +, -, *, /) from standard input. Evaluate the expression in Reverse Polish Notation (RPN) and print the result. Division truncates toward zero. The tournament rules are absolute, displayed on the massive arena screen: 1 <= tokens <= 100 The judges have prepared these official test scenarios: Input: 2 1 + 3 * Output: 9 The starting bell is about to ring. The challenger adjusts their gloves and cracks their knuckles. Write the algorithm that will deliver a knockout. The universe is watching, and there are no ties in the Galactic Colosseum. The path to mastering Evaluate Reverse Polish Notation — Level 8 is not one that can be walked in a single step. It demands patience, precision, and a deep respect for the boundaries that shape the problem. Many adventurers before you have attempted this trial and failed, their code crashing against the very constraints that the elders inscribed. But you have the tools. You have the training. You have reached the Quantum Coder tier, and that alone means the council believes in your potential. Look once more at the examples above. Trace the logic with your finger if you must. Consider the time and memory limits carefully, for they are not suggestions but strict laws of the arena. When you are ready, commit your solution. Let the compiler run. Let the test cases judge your work. If your code is true, the gates will open and you will move closer to the ultimate rank. If not, study the failure, sharpen your algorithm, and try again. For in the halls of CodeTikki, the only thing more important than success is the wisdom gained from the attempt. Remember that the Quantum Coder challenge is designed to test not just knowledge, but character. Every edge case is a lesson. Every time limit is a teacher. Every hidden test is a guardian at the gate. Do not rush. Let your code breathe. Let it be as clean as a mountain stream. When the final test passes, you will know that you have earned the title. Until then, code with courage, test with care, and never stop learning.