Create 150-evaluate-reverse-polish-notation.js

Author: everthis

150-evaluate-reverse-polish-notation.js

@@ -0,0 +1,21 @@
+/**
+ * @param {string[]} tokens
+ * @return {number}
+ */
+const evalRPN = function(tokens) {
+  const stack = []
+  for (let token of tokens) {
+    if (token === '+') {
+      stack.push(stack.pop() + stack.pop())
+    } else if (token === '-') {
+      stack.push(-stack.pop() + stack.pop())
+    } else if (token === '*') {
+      stack.push(stack.pop() * stack.pop())
+    } else if (token === '/') {
+      stack.push(Math.trunc((1 / stack.pop()) * stack.pop()))
+    } else {
+      stack.push(parseInt(token))
+    }
+  }
+  return stack[0]
+}