Problem description:
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
Every close bracket has a corresponding open bracket of the same type.
Solution description:
Create a stack to store opening brackets.
Whenever a closing bracket is encountered, check for it's corresponding opening bracket in the stack.top(), if they match then pop the stack, if they don't declare invalid.
If the stack becomes empty, after all characters in the expression have been read, it means all brackets were matched correctly and expression is valid.
If not invalid expression
Problem description:
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
Every close bracket has a corresponding open bracket of the same type.
Solution description:
Create a stack to store opening brackets.
Whenever a closing bracket is encountered, check for it's corresponding opening bracket in the stack.top(), if they match then pop the stack, if they don't declare invalid.
If the stack becomes empty, after all characters in the expression have been read, it means all brackets were matched correctly and expression is valid.
If not invalid expression