stack apps added

Author: hemangsk

Data Structures/balancedParenthesisUsingStack.py

@@ -0,0 +1,44 @@
+#Program to validate parenthesis
+#Using Stack
+
+class Stack:
+
+    def __init__(self):
+        self.stack = []
+
+    def push(self, item):
+        self.stack.append(item)
+
+    def pop(self):
+        return self.stack.pop()
+
+    def isEmpty(self):
+        return self.stack == []
+
+    def top(self):
+        if(self.size()!=0):
+            item = self.stack[self.size()-1]
+            return item
+
+    def size(self):
+        return len(self.stack)
+
+
+def parenthesisCheck(string):
+    """ Function to check parenthesis using Stack class """
+    s = Stack()
+    length = len(string)
+
+    for x in range(0, length):
+        if(string[x] == '('):
+            s.push(string[x])
+        elif(string[x] == ')' and s.isEmpty() == False):
+            s.pop()
+
+    if(s.isEmpty()):
+        return True
+    else:
+        return False
+
+print(parenthesisCheck("(()(()")) #False
+print(parenthesisCheck("(())"))   #True