Given a string s of '(' , ')' and lowercase English characters.Your task is to remove the minimum number of parentheses ( '(' or ')', in any positions ) so that the resulting parentheses string is valid and return any valid string.Formally, a parentheses string is valid if and only if:It is the empty string, contains only lowercase characters, orIt can be written as AB (A concatenated with B), where A and B are valid strings, orIt can be written as (A), where A is a valid string. Example 1:Input: s = "lee(t(c)o)de)"Output: "lee(t(c)o)de"Explanation: "lee(t(co)de)" , "lee(t(c)ode)" would also be accepted.
Question
Given a string s of '(' , ')' and lowercase English characters.Your task is to remove the minimum number of parentheses ( '(' or ')', in any positions ) so that the resulting parentheses string is valid and return any valid string.Formally, a parentheses string is valid if and only if:It is the empty string, contains only lowercase characters, orIt can be written as AB (A concatenated with B), where A and B are valid strings, orIt can be written as (A), where A is a valid string. Example 1:Input: s = "lee(t(c)o)de)"Output: "lee(t(c)o)de"Explanation: "lee(t(co)de)" , "lee(t(c)ode)" would also be accepted.
Solution
This problem can be solved using a stack data structure. Here are the steps:
- Initialize an empty stack and an empty string result.
- Iterate over each character in the string.
- If the character is an opening parenthesis '(' or a lowercase English character, add it to the result string and if it's an opening parenthesis, also push its index into the stack.
- If the character is a closing parenthesis ')', check if the stack is not empty. If the stack is not empty, it means there is a matching opening parenthesis for this closing parenthesis, so just add it to the result string. If the stack is empty, ignore this closing parenthesis because there is no matching opening parenthesis for it.
- After the iteration, there might be some opening parentheses in the stack which don't have matching closing parentheses. These opening parentheses should be removed from the result string.
- Iterate over the stack, and for each index in the stack, remove the character at that index from the result string.
- Finally, return the result string.
Here is a Python code snippet that implements the above steps:
def minRemoveToMakeValid(s):
stack = []
s = list(s)
for i, char in enumerate(s):
if char == '(':
stack.append(i)
elif char == ')':
if stack:
stack.pop()
else:
s[i] = ''
while stack:
s[stack.pop()] = ''
return ''.join(s)
In the example "lee(t(c)o)de)", the function will return "lee(t(c)o)de".
Similar Questions
Take the string input of parentheses from the user, return the balanced string that can be produced from it,perform deletion if there are unbalanced parentheses.if there are no balanced parentheses it should return NoneFor example, given "(())((", you could return "(())".Given "))()()(", you could return "()()".Sample Test CasesTest Case 1:Expected Output:enter·the·string:·(())(((())Test Case 2:Expected Output:enter·the·string:·))()()(()()
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. Example 1:Input: s = "()"Output: trueExample 2:Input: s = "()[]{}"Output: trueExample 3:Input: s = "(]"Output: false Constraints:1 <= s.length <= 104s consists of parentheses only '()[]{}'.
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Valid ParenthesesRachel is studying nested structures and wants to validate if a given string of parentheses is valid. A valid string has matching opening and closing parentheses in the correct order.Constraints:NAExample:Sample Input:()[]{}Sample Output:trueExplanation:In the above example, the string is valid because every opened parentheses is closed in the correct order and the output is truePublic Test Cases:# INPUT EXPECTED OUTPUT1 ()[]{}true
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