Given a string of brackets, task is to find the number of pairs of brackets involved in a balanced sequence in a given range.
Input : ((())(() Range : 1 5 Range : 3 8 Output : 2 2 Explanation : In range 1 to 5 ((()), there are the two pairs. In range 3 to 8 ()) ((), there are the two pairs. Input : )()())) Range : 1 2 Range : 4 7 Output : 0 1 Explanation : In range 1 to 2 )( there is no any pair. In range 4 to 7 ())), there is the only pair
Prerequisite : Segment Trees
Here, in segment tree, for each node, keep some simple elements, like integers or sets or vectors or etc.
For each node keep three integers :
1. t = Answer for the interval.
2. o = The number of opening brackets ‘(‘ remaining after deleting the brackets those who belong to the correct bracket sequence in this interval whit length t.
3. c = The number of closing brackets ‘)’ remaining after deleting the brackets those who belong to the correct bracket sequence in this interval whit length t.
Now, having these variables, queries can be answered easily using segment tree.
Below is the implementation of above approach :
- Count pairs of parentheses sequences such that parentheses are balanced
- Print all combinations of balanced parentheses
- Check for balanced parentheses in an expression
- Check for balanced parentheses in Python
- Check for balanced parentheses in an expression | O(1) space
- Length of longest balanced parentheses prefix
- Number of ways to insert two pairs of parentheses into a string of N characters
- Remove Invalid Parentheses
- Find the number of valid parentheses expressions of given length
- Minimum number of Parentheses to be added to make it valid
- Sorted Array to Balanced BST
- Convert a normal BST to Balanced BST
- Check if concatenation of two strings is balanced or not
- Practice questions on Height balanced/AVL Tree
- Number of balanced bracket subsequence of length 2 and 4
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