Added postfix expression evaluation problem

README.md

@@ -27,7 +27,9 @@ Collection of interview questions with Unit Tests. Problems includes Data Struct
   - [Minimum Stack](src/_DataStructures_/Stack/min-stack)
   - [Balanced Parenthesis](src/_DataStructures_/Stack/balanced-parenthesis)
   - [Postfix Expression Evaluation](src/_DataStructures_/Stack/postfix-expression-evaluation)
-
+  - [Remove Consecutive Repeated Digits](src/_DataStructures_/Stack/remove-consecutive-repeated-digits)
+  - [Implement 2 Stacks using Single Array](src/_DataStructures_/Stack/2-stacks-using1-array)
+
 
 - [Queue](src/_DataStructures_/Queue)
   - [Weave](src/_DataStructures_/Queue/weave)

src/_DataStructures_/Stack/remove-consecutive-repeated-digits/index.js

@@ -0,0 +1,25 @@
+/**
+ * Given an integer N, remove consecutive repeated digits from it.
+ * Input:133445
+ * Output:1345
+ */
+
+const Stack = require('../index');
+
+
+function removeConsecutiveDigits(no) {
+    let s = new Stack();
+    let newNo = "";
+    //initally push first digit into stack
+    newNo += no[0];
+    s.push(no[0]);
+    for (let i = 1; i < no.length; i++) {
+        const digit = no[i];
+        //if stack top and incoming digit is same ignore it else append to newNo.
+        if (s.peek() !== digit) {
+            newNo += digit;
+            s.push(digit);
+        }
+    }
+    return newNo
+}