Time: 17 ms (70.72%), Space: 11.9 MB (93.63%) - LeetHub

0150-evaluate-reverse-polish-notation/0150-evaluate-reverse-polish-notation.cpp

@@ -0,0 +1,31 @@
+class Solution {
+public:
+    int solve(string op,int x,int y)
+    {
+        if(op=="+")return x+y;
+        if(op=="-")return x-y;
+        if(op=="*")return long(x)*long(y);
+        if(op=="/")return x/y;
+        return -1;
+    }
+    int evalRPN(vector<string>& tokens) {
+        stack<int> st;
+        for(int i=0;i<tokens.size();i++)
+        {
+            if(tokens[i]=="+"||tokens[i]=="-"||tokens[i]=="*"||tokens[i]=="/")
+            {
+                int y=st.top();
+                st.pop();
+                int x=st.top();
+                st.pop();
+                st.push(solve(tokens[i],x,y));
+            }
+            else
+            {
+                st.push(stoi(tokens[i]));
+            }
+        }
+        return st.top();
+
+    }
+};