Problem:
Score : 400 points

Problem Statement

Takahashi is going to buy N items one by one.

The price of the i-th item he buys is A_i yen (the currency of Japan).

He has M discount tickets, and he can use any number of them when buying an item.

If Y tickets are used when buying an item priced X yen, he can get the item for \frac{X}{2^Y} (rounded down to the nearest integer) yen.

What is the minimum amount of money required to buy all the items?

Constraints

All values in input are integers.

1 \leq N, M \leq 10^5

1 \leq A_i \leq 10^9

Input

Input is given from Standard Input in the following format:

N M
A_1 A_2 ... A_N

Output

Print the minimum amount of money required to buy all the items.

Sample Input 1

3 3
2 13 8

Sample Output 1

9

We can buy all the items for 9 yen, as follows:

Buy the 1-st item for 2 yen without tickets.

Buy the 2-nd item for 3 yen with 2 tickets.

Buy the 3-rd item for 4 yen with 1 ticket.

Sample Input 2

4 4
1 9 3 5

Sample Output 2

6

Sample Input 3

1 100000
1000000000

Sample Output 3

0

We can buy the item priced 1000000000 yen for 0 yen with 100000 tickets.

Sample Input 4

10 1
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000

Sample Output 4

9500000000

Solution in Go (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

func solve(sc *scanner, wr *bufio.Writer) {
	n, m := sc.getInt2()
	pq := newIntPriorityQueue()
	for i := 0; i < n; i++ {
		a := sc.getInt()
		heap.Push(pq, a)
	}

	for i := 0; i < m; i++ {
		(*pq)[0] /= 2
		heap.Fix(pq, 0)
	}

	ans := sum(*pq...)
	fmt.Fprintln(wr, ans)
}

type intPriorityQueue []int

func newIntPriorityQueue() *intPriorityQueue {
	pq := new(intPriorityQueue)
	heap.Init(pq)
	return pq
}

func (pq intPriorityQueue) Len() int           { return len(pq) }
func (pq intPriorityQueue) Less(i, j int) bool { return pq[i] > pq[j] }
func (pq intPriorityQueue) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }
func (pq *intPriorityQueue) Push(x interface{}) {
	*pq = append(*pq, x.(int))
}
func (pq *intPriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	ret := old[n-1]
	*pq = old[0 : n-1]
	return ret
}

func main() {
	sc := newScanner()
	wr := bufio.NewWriter(os.Stdout)
	maxBufSize := int(1e8)
	sc.Buffer(make([]byte, 4096), maxBufSize)
	sc.Split(bufio.ScanWords)

	solve(sc, wr)
	wr.Flush()
}

// input ------------------------
type scanner struct {
	*bufio.Scanner
}

func newScanner() *scanner {
	sc := bufio.NewScanner(os.Stdin)
	return &scanner{sc}
}
func (sc *scanner) getInt() int {
	sc.Scan()
	ret, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return ret
}
func (sc *scanner) getInt2() (int, int) {
	return sc.getInt(), sc.getInt()
}
func (sc *scanner) getInt3() (int, int, int) {
	return sc.getInt(), sc.getInt(), sc.getInt()
}
func (sc *scanner) getInt4() (int, int, int, int) {
	return sc.getInt(), sc.getInt(), sc.getInt(), sc.getInt()
}
func (sc *scanner) getInts(n int) []int {
	ret := make([]int, n)
	for i := range ret {
		ret[i] = sc.getInt()
	}
	return ret
}
func (sc *scanner) getString() string {
	sc.Scan()
	return sc.Text()
}
func (sc *scanner) getRunes() []rune {
	return []rune(sc.getString())
}
func (sc *scanner) getFloat() float64 {
	sc.Scan()
	ret, err := strconv.ParseFloat(sc.Text(), 64)
	if err != nil {
		panic(err)
	}
	return ret
}
func (sc *scanner) getFloats(n int) []float64 {
	ret := make([]float64, n)
	for i := range ret {
		ret[i] = sc.getFloat()
	}
	return ret
}

// math ----------------------------
func sum(ns ...int) int {
	var sum int
	for _, n := range ns {
		sum += n
	}
	return sum
}

func max(ns ...int) int {
	max := ns[0]
	for i := 1; i < len(ns); i++ {
		if max < ns[i] {
			max = ns[i]
		}
	}
	return max
}

func min(ns ...int) int {
	min := ns[0]
	for i := 1; i < len(ns); i++ {
		if min > ns[i] {
			min = ns[i]
		}
	}
	return min
}

func pow(a, b int) int {
	ret := 1
	for b > 0 {
		if b&1 > 0 {
			ret = ret * a
		}
		a = a * a
		b >>= 1
	}
	return ret
}