Merge pull request #987 from shuvojitss/pr-4

Added Stack Permutation program

Algorithms_and_Data_Structures/Stack/Stack_permutation.py

@@ -0,0 +1,21 @@
+def is_stack_permutation(input, output):
+    stack = []  # Use list as a stack
+    j = 0  # Pointer for the output sequence
+    for i in range(len(input)):
+        # Push the current element of the input array onto the stack
+        stack.append(input[i])
+        # Check if the top of the stack matches the output array
+        while stack and stack[-1] == output[j]:
+            stack.pop()
+            j += 1  # Move to the next element in output
+    # If j has reached the length of output, then output is a valid permutation
+    return j == len(output)
+
+# Example usage
+input = [1, 2, 3]
+output = [2, 1, 3]
+
+if is_stack_permutation(input, output):
+    print("Yes, it is a stack permutation")
+else:
+    print("No, it is not a stack permutation")

Project-Structure.md

@@ -148,6 +148,7 @@
     * [Postfixtoprefix](Algorithms_and_Data_Structures/Stack/PostfixToPrefix.py)
     * [Prefixtoinfix](Algorithms_and_Data_Structures/Stack/PrefixToInfix.py)
     * [Prefixtopostfix](Algorithms_and_Data_Structures/Stack/PrefixToPostfix.py)
+    * [Stack Permutation](Algorithms_and_Data_Structures/Stack/Stack_permutation.py)
     * [Stack](Algorithms_and_Data_Structures/Stack/stack.py)
   * Strings
     * [Longest Palindromic Substring](Algorithms_and_Data_Structures/Strings/longest_palindromic_substring.py)