Merge pull request #999 from shuvojitss/pr-5

 Added Min Stack program

Algorithms_and_Data_Structures/Stack/Min_Stack.py

@@ -0,0 +1,61 @@
+class MinStack:
+    def __init__(self):
+        self.st = []
+        self.mini = float('inf')
+
+    def push(self, value: int):
+        val = value
+        if not self.st:
+            self.mini = val
+            self.st.append(val)
+        else:
+            if val < self.mini:
+                self.st.append(2 * val - self.mini)
+                self.mini = val
+            else:
+                self.st.append(val)
+        print(f"Element Pushed: {value}")
+
+    def pop(self):
+        if not self.st:
+            print("Stack is empty, cannot pop")
+            return
+        el = self.st.pop()
+        if el < self.mini:
+            print(f"Element popped: {self.mini}")
+            self.mini = 2 * self.mini - el
+        else:
+            print(f"Element popped: {el}")
+
+    def top(self) -> int:
+        if not self.st:
+            print("Stack is empty")
+            return -1
+        el = self.st[-1]
+        if el < self.mini:
+            top_element = self.mini
+        else:
+            top_element = el
+        print(f"Top Most Element is: {top_element}")
+        return top_element
+
+    def getMin(self) -> int:
+        if not self.st:
+            print("Stack is empty")
+            return -1
+        print(f"Minimum Element in the stack is: {self.mini}")
+        return self.mini
+
+# Sample input as per the question
+stack = MinStack()
+stack.push(9)
+stack.push(15)
+stack.getMin()
+stack.push(1)
+stack.getMin()
+stack.pop()
+stack.getMin()
+stack.push(4)
+stack.getMin()
+stack.pop()
+stack.top()

Project-Structure.md

@@ -144,6 +144,7 @@
     * [Balanced Parentheses Checker](Algorithms_and_Data_Structures/Stack/Balanced_parentheses_checker.py)
     * [Infixtopostifix](Algorithms_and_Data_Structures/Stack/InfixToPostifix.py)
     * [Infixtoprefix](Algorithms_and_Data_Structures/Stack/InfixToPrefix.py)
+    * [Min Stack](Algorithms_and_Data_Structures/Stack/Min_Stack.py)
     * [Postfixtoinfix](Algorithms_and_Data_Structures/Stack/PostfixToInfix.py)
     * [Postfixtoprefix](Algorithms_and_Data_Structures/Stack/PostfixToPrefix.py)
     * [Prefixtoinfix](Algorithms_and_Data_Structures/Stack/PrefixToInfix.py)