k using the quadratic equation k = min(n, int((-1 + sqrt(1 + 8 * maxSum)) / 2)).currentSum to k * (k + 1) / 2 and count to k.bannedSet from the banned array.bannedSet and for each banned number b that is less than or equal to k, subtract b from currentSum and decrement count.k + 1 to n and for each non-banned number, add it to currentSum and increment count until currentSum exceeds maxSum.count.