Wabbit is playing a game with $n$ bosses numbered from $1$ to $n$. The bosses can be fought in any order. Each boss needs to be defeated exactly once. There is a parameter called boss bonus which is initially $0$.

When the $i$-th boss is defeated, the current boss bonus is added to Wabbit's score, and then the value of the boss bonus increases by the point increment $c_i$. Note that $c_i$ can be negative, which means that other bosses now give fewer points.

However, Wabbit has found a glitch in the game. At any point in time, he can reset the playthrough and start a New Game Plus playthrough. This will set the current boss bonus to $0$, while all defeated bosses remain defeated. The current score is also saved and does not reset to zero after this operation. This glitch can be used at most $k$ times. He can reset after defeating any number of bosses (including before or after defeating all of them), and he also can reset the game several times in a row without defeating any boss.

Help Wabbit determine the maximum score he can obtain if he has to defeat all $n$ bosses.


-----Input-----

The first line of input contains two spaced integers $n$ and $k$ ($1 \leq n \leq 5 \cdot 10^5$, $0 \leq k \leq 5 \cdot 10^5$), representing the number of bosses and the number of resets allowed.

The next line of input contains $n$ spaced integers $c_1,c_2,\ldots,c_n$ ($-10^6 \leq c_i \leq 10^6$), the point increments of the $n$ bosses.


-----Output-----

Output a single integer, the maximum score Wabbit can obtain by defeating all $n$ bosses (this value may be negative).


-----Examples-----

Input
3 0
1 1 1
Output
3
Input
5 1
-1 -2 -3 -4 5
Output
11
Input
13 2
3 1 4 1 5 -9 -2 -6 -5 -3 -5 -8 -9
Output
71


-----Note-----

In the first test case, no resets are allowed. An optimal sequence of fights would be

Fight the first boss $(+0)$. Boss bonus becomes equal to $1$.

Fight the second boss $(+1)$. Boss bonus becomes equal to $2$.

Fight the third boss $(+2)$. Boss bonus becomes equal to $3$.

Thus the answer for the first test case is $0+1+2=3$.

In the second test case, it can be shown that one possible optimal sequence of fights is

Fight the fifth boss $(+0)$. Boss bonus becomes equal to $5$.

Fight the first boss $(+5)$. Boss bonus becomes equal to $4$.

Fight the second boss $(+4)$. Boss bonus becomes equal to $2$.

Fight the third boss $(+2)$. Boss bonus becomes equal to $-1$.

Reset. Boss bonus becomes equal to $0$.

Fight the fourth boss $(+0)$. Boss bonus becomes equal to $-4$.

Hence the answer for the second test case is $0+5+4+2+0=11$.

Source: codeforces | Difficulty: HARD
Tags: Greedy algorithms

Mathematics

Constructive algorithms


Solutions:
(n, k) = map(lambda x: int(x), input().split())
v = list(map(lambda x: int(x), input().split()))
v.sort()
k += 1
q = 0
s = 0
while len(v) > 0 and q >= 0:
	s += q
	q += v.pop()
v.append(q)
d = len(v) % k - 1
for i in range(len(v)):
	if d >= i % k:
		p = len(v) // k - i // k
	else:
		p = len(v) // k - i // k - 1
	s += v[len(v) - i - 1] * p
print(s)


import sys
input = lambda : sys.stdin.readline()

def RL():
	return map(int, sys.stdin.readline().split())

def RLL():
	return list(map(int, sys.stdin.readline().split()))

def N():
	return int(input())

def print_list(l):
	print(' '.join(map(str, l)))
(n, k) = RL()
a = RLL()
a.sort()
p = list(range(n))
if k > 0:
	s = [0]
	for i in a[::-1]:
		s.append(i + s[-1])
	s = s[1:][::-1]
	delta = 0
	r = k
	now = 0
	for i in range(1, n):
		p[i] -= delta
		if p[i] == now:
			continue
		if s[i] >= 0:
			for i in range(i + 1, n):
				p[i] -= delta
			break
		delta += 1
		p[i] = now
		r -= 1
		if r == 0:
			r = k
			now += 1
res = 0
for i in range(n):
	res += p[i] * a[i]
print(res)


(n, k) = map(int, input().split())
a = sorted(list(map(int, input().split())))
p = list(range(n))
if k > 0:
	s = [0]
	for i in a[::-1]:
		s.append(i + s[-1])
	s = s[1:][::-1]
	delta = 0
	r = k
	now = 0
	for i in range(1, n):
		p[i] -= delta
		if p[i] == now:
			continue
		if s[i] >= 0:
			for i in range(i + 1, n):
				p[i] -= delta
			break
		delta += 1
		p[i] = now
		r -= 1
		if r == 0:
			r = k
			now += 1
res = 0
for i in range(n):
	res += p[i] * a[i]
print(res)