m=1 ()
'(' < ')'
k=1 (())
k=2 ()()
i
s1 s2 s3 s4 ( ....... count1 = dp[i+1,b+1]
s1 s2 s3 s4 ) ....... count2
if count1 >= k : '('
else : ')'; k -= count1
dp[?] = '('..... + ')'.....
? = i, b
dp[i,b] = dp[i+1,b+1] + (b?dp[i+1,b-1]:0)
dp[n, 0] = 1
dp[n, не ноль] = 0
balance=0
for i=0..n-1
if s[i] == '('
balance += 1
else if (balance > 0)
balance -= 1
else
не правильная
if (balance > 0)
не правильная