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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /eval_reverse_polish_notation.rs
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Diffstat (limited to 'eval_reverse_polish_notation.rs')
-rw-r--r--eval_reverse_polish_notation.rs29
1 files changed, 29 insertions, 0 deletions
diff --git a/eval_reverse_polish_notation.rs b/eval_reverse_polish_notation.rs
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+++ b/eval_reverse_polish_notation.rs
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+struct Solution;
+
+impl Solution {
+ pub fn eval_rpn(tokens: Vec<String>) -> i32 {
+ tokens.iter().fold(Vec::new(), |mut stack, x| {
+ if let Ok(x) = x.parse() {
+ stack.push(x);
+ } else if let (Some(rhs), Some(lhs)) = (stack.pop(), stack.pop()) {
+ stack.push(match x.as_str() {
+ "+" => lhs + rhs,
+ "-" => lhs - rhs,
+ "*" => lhs * rhs,
+ "/" => lhs / rhs,
+ _ => unreachable!()
+ })
+ }
+ stack
+ }) [0]
+ }
+}
+
+fn main() {
+ let tokens1 = ["2","1","+","3","*"];
+ let tokens2 = ["4","13","5","/","+"];
+ let tokens3 = ["10","6","9","3","+","-11","*","/","*","17","+","5","+"];
+ println!("{}", Solution::eval_rpn(tokens1));
+ println!("{}", Solution::eval_rpn(tokens2));
+ println!("{}", Solution::eval_rpn(tokens3));
+}