20240520 Finished

src/problem/mod.rs

@@ -135,4 +135,5 @@ mod p56_merge_intervals;
 mod p57_insert_interval;
 mod p452_minimum_number_of_arrows_to_burst_balloons;
 mod p71_simplify_path;
-mod p155_min_stack;
+mod p155_min_stack;
+mod p150_evaluate_reverse_polish_notation;

src/problem/p150_evaluate_reverse_polish_notation.rs

@@ -0,0 +1,43 @@
+/**
+ * [150] Evaluate Reverse Polish Notation
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn eval_rpn(tokens: Vec<String>) -> i32 {
+        let mut stack = vec![];
+
+        for token in tokens {
+            if let Ok(num) = token.parse::<i32>() {
+                stack.push(num);
+            } else {
+                let second = stack.pop().unwrap();
+                let first = stack.pop().unwrap();
+
+                match token.as_str() {
+                    "+" => stack.push(first + second),
+                    "-" => stack.push(first - second),
+                    "*" => stack.push(first * second),
+                    "/" => stack.push(first / second),
+                    _ => {},
+                }
+            }
+        }
+
+        stack[0]
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_150() {
+        assert_eq!(9, Solution::eval_rpn(vec_string!["2","1","+","3","*"]));
+    }
+}