380C - Sereja and Brackets - CodeForces Solution

import os,sys
from io import BytesIO, IOBase
from array import array
 
def construct(n,x,si):
    left = array('i',[0]*(si<<1))
    right = array('i',[0]*(si<<1))
    tree = array('i',[0]*(si<<1))
    for i in range(si,si+n):
        if x[i-si] == '(':
            left[i] = 1
        else:
            right[i] = 1
    a,b = si>>1,si
    while a:
        for i in range(a,b):
            z = min(left[i<<1],right[i<<1|1])
            tree[i] = tree[i<<1]+tree[i<<1|1]+2*z
            left[i] = left[i<<1]+left[i<<1|1]-z
            right[i] = right[i<<1]+right[i<<1|1]-z
        a,b = a>>1,b>>1
    return left,right,tree
 
def query(tree,left,right,l,r,si):
    l,r = l+si-1,r+si-1
    partl,partr = [],[]
    while l < r:
        if l&1:
            partl.append(l)
            l += 1
        if not r&1:
            partr.append(r)
            r -= 1
        l,r = l>>1,r>>1
    if l == r:
        partl.append(l)
    ans,le = 0,0
    for i in partl+partr[::-1]:
        tk = min(le,right[i])
        ans += 2*tk+tree[i]
        le += left[i]-tk
    return ans
 
def main():
    s = input().strip()
    n = len(s)
    si = 1<<n.bit_length()-(not n&n-1)
    left,right,tree = construct(n,s,si)
    for _ in range(int(input())):
        l,r = map(int,input().split())
        print(query(tree,left,right,l,r,si))
 
BUFSIZE = 8192
class FastIO(IOBase):
    newlines = 0
    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None
    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()
    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()
    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)
class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")
if __name__ == "__main__":
    main()