Add Stack which support Min() using two stacks in Python

Implemented a new Minstack class which works like a stack and gives minimum  of stack  in O(1) using an extra auxiliary stack

Author: Rishabhsaini21

data_structures/min_stack_with_twostacks

@@ -0,0 +1,49 @@
+class MinStack:
+    def __init__(self):
+        self.st = []
+        # main stack for storing elements
+        self.minSt = []
+        # auxiliary stack for finding minimum in O(1) time space O(N) because of this auxiliary stack using
+  # pushing new element
+    def push(self, x):
+        self.st.append(x)
+        
+        # If minSt is empty or new element is smaller than 
+        # the top of minSt, push it because if it is empty then coming element will be minimum and if coming element is smaller than previous
+        if not self.minSt or x <= self.minSt[-1]:
+            self.minSt.append(x)
+        
+    # Pop the top element
+    def pop(self):
+        if not self.st:
+          return None
+        value = self.st.pop()
+        if value == self.minSt[-1]:
+            self.minSt.pop()
+        return value
+
+    # Return top element
+    def peek(self):
+        if not self.st:
+            return None
+        return self.st[-1]
+
+    # Get the minimum element
+    def getMin(self):
+        if not self.minSt:
+            return None
+        return self.minSt[-1]
+
+
+if __name__ == '__main__':
+    st = MinStack()
+    # making new minstack object
+    #adding new elements
+    st.push(18)
+    st.push(19)
+    st.push(29)
+    st.push(15)
+    st.push(16)
+    
+    print(st.getMin())
+    # should return 15