Can you help me to solve this problem?
Redundant Parentheses need an approach
@rohit267 Hey,The idea is to use stack. Iterate through the given expression and for each character in the expression, if the character is a open parenthesis ‘(‘ or any of the operators or operands, push it to the top of the stack. If the character is close parenthesis ‘)’, then pop characters from the stack till matching open parenthesis ‘(‘ is found and a counter is used, whose value is incremented for every character encountered till the opening parenthesis ‘(‘ is found. If the number of characters encountered between the opening and closing parenthesis pair, which is equal to the value of the counter, is less than or equal to 1, then a pair of duplicate parenthesis is found else there is no occurrence of redundant parenthesis pairs. For example, (((a+b))+c) has duplicate brackets around “a+b”. When the second “)” after a+b is encountered, the stack contains “((“. Since the top of stack is a opening bracket, it can be concluded that there are duplicate brackets.
Hope it helps
we are incrementing the counter then it will never be less then or equal to 1?
@rohit267 we are setting it to 0 after every round ,see this code:
** bool findDuplicateparenthesis(string str)
{
// create a stack of characters
stack< char > Stack;
// Iterate through the given expression
for ( char ch : str)
{
// if current character is close parenthesis ')'
if (ch == ')' )
{
// pop character from the stack
char top = Stack.top();
Stack.pop();
// stores the number of characters between a
// closing and opening parenthesis
// if this count is less than or equal to 1
// then the brackets are redundant else not
int elementsInside = 0;
while (top != '(' )
{
elementsInside++;
top = Stack.top();
Stack.pop();
}
if (elementsInside < 1) {
return 1;
}
}
// push open parenthesis '(', operators and
// operands to stack
else
Stack.push(ch);
}
// No duplicates found
return false ;
}
**
i have to open disscuss.codingblocks.com to see your replies, the chat is not working
well thanks, let me try once.
@rohit267 bhai logic galat hai ,upar wala code refernce ke lie use kro ‘)’ push kra hua hai apne ,ulta hoga,plese see above code.