44 lines
989 B
Rust
44 lines
989 B
Rust
/**
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* [150] Evaluate Reverse Polish Notation
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*/
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pub struct Solution {}
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// submission codes start here
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impl Solution {
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pub fn eval_rpn(tokens: Vec<String>) -> i32 {
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let mut stack = vec![];
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for token in tokens {
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if let Ok(num) = token.parse::<i32>() {
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stack.push(num);
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} else {
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let second = stack.pop().unwrap();
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let first = stack.pop().unwrap();
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match token.as_str() {
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"+" => stack.push(first + second),
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"-" => stack.push(first - second),
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"*" => stack.push(first * second),
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"/" => stack.push(first / second),
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_ => {}
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}
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}
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}
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stack[0]
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}
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}
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// submission codes end
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_150() {
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assert_eq!(9, Solution::eval_rpn(vec_string!["2", "1", "+", "3", "*"]));
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}
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}
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