easyStackPattern: Stack
Validate Stack Sequence Solution
Problem Statement
You are given a sequence of integers where 27 represents a push operation and 91 represents a pop operation. Implement a function to validate if the given sequence is properly nested using a stack data structure.
Examples
Example 1:
Input:[27, 27, 91, 91]
Output:true
Explanation: Properly nested sequence of push and pop operations
Example 2:
Input:[27, 91, 27, 91]
Output:true
Explanation: Properly nested sequence of push and pop operations
Example 3:
Input:[27, 27, 91]
Output:false
Explanation: More push operations than pop operations
Constraints
- The input string can be arbitrarily long.
- The input string can contain any character, but only the parentheses ('()', '[]', '{}') are relevant for determining validity.
- The parentheses can be nested to any depth.
Time: O(n) Space: O(n)
Use a stack to keep track of opening commands and iterate over the sequence of commands in O(n) time complexity
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