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Valid Parentheses

Certification: Advanced Level Accuracy: 37.5% Submissions: 8 Points: 8

Write a C# function to determine if a given string contains valid parentheses. An input string is valid if: 1. Open brackets must be closed by the same type of brackets. 2. Open brackets must be closed in the correct order. 3. Every close bracket has a corresponding open bracket of the same type.

Example 1
    
  
  • Input: s = "()"
    • 
  
  • Output: true
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  • Explanation: 
    
      
      
    • The string contains one pair of parentheses that open and close correctly.
      • 
    
    
  
    •
Example 2
    
  
  • Input: s = "([)]"
    • 
  
  • Output: false
    • 
  
  • Explanation: 
    
      
      
    • The brackets are not closed in the correct order (closing ) before closing ]).
      • 
    
    
  
    •
Constraints
    
  
  • 1 ≤ s.length ≤ 10^4
    • 
  
  • s consists of only '(', ')', '{', '}', '[', and ']'
    • 
  
  • Time Complexity: O(n)
    • 
  
  • Space Complexity: O(n)
    •
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Hint
Solution

Solution Hints

    
  
  • Use a stack data structure to track opening brackets
    • 
  
  • When encountering a closing bracket, check if it matches the most recent opening bracket
    • 
  
  • The string is valid if all brackets are matched and closed in the correct order
    • 
  
  • If the stack is empty at the end and all characters have been processed, the string is valid
    •

Steps to solve by this approach:

 Step 1: Create a stack to store opening brackets.
 Step 2: Iterate through each character in the string.
 Step 3: If the character is an opening bracket ('(', '[', '{'), push it onto the stack.
 Step 4: If the character is a closing bracket (')', ']', '}'), check if the stack is empty. If it is, return false.
 Step 5: If the stack is not empty, pop the top element and check if it matches the current closing bracket.
 Step 6: If the brackets don't match, return false.
 Step 7: After processing all characters, return true if the stack is empty (all brackets were matched).

Submitted Code :