Problem:


Score : 400 points

Problem Statement

There are N integers, A_1, A_2, ..., A_N, arranged in a row in this order.

You can perform the following operation on this integer sequence any number of times:

Operation: Choose an integer i satisfying 1 \leq i \leq N-1. Multiply both A_i and A_{i+1} by -1.

Let B_1, B_2, ..., B_N be the integer sequence after your operations.

Find the maximum possible value of B_1 + B_2 + ... + B_N.

Constraints

All values in input are integers.

2 \leq N \leq 10^5

-10^9 \leq A_i \leq 10^9

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N

Output

Print the maximum possible value of B_1 + B_2 + ... + B_N.

Sample Input 1

3
-10 5 -4

Sample Output 1

19

If we perform the operation as follows:

Choose 1 as i, which changes the sequence to 10, -5, -4.

Choose 2 as i, which changes the sequence to 10, 5, 4.

we have B_1 = 10, B_2 = 5, B_3 = 4. The sum here, B_1 + B_2 + B_3 = 10 + 5 + 4 = 19, is the maximum possible result.

Sample Input 2

5
10 -4 -8 -11 3

Sample Output 2

30

Sample Input 3

11
-1000000000 1000000000 -1000000000 1000000000 -1000000000 0 1000000000 -1000000000 1000000000 -1000000000 1000000000

Sample Output 3

10000000000

The output may not fit into a 32-bit integer type.



Sample input:
3
-10 5 -4


Sample output:
19

Submission status: Accepted

Solution code:
n = int(input())
A = [int(a) for a in input().split()]

num_negative = sum(a < 0 for a in A)
A_abs = [abs(a) for a in A]

if num_negative % 2 == 0:
    result = sum(A_abs)
else:
    result = sum(A_abs) - 2 * min(A_abs)

print(result)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))



signA = sum([1 for a in A if a<0])

absA = [abs(a) for a in A]
absA.sort()

sumA = sum(absA)
      
         
if any([a==0 for a in A]):
  print(sumA)
elif signA%2==0:
  print(sumA)
elif signA%2!=0:
  print(sumA - 2*absA[0])

Submission status: Accepted

Solution code:
N = int(input())
A = [int(_) for _ in input().split()]

absmin = float('inf')
minusnum = 0
ans = 0

for i in A:
    ans += abs(i)
    if abs(i) < absmin:
        absmin = abs(i)
    if i < 0:
        minusnum += 1

if minusnum % 2 == 0:
    print(ans)
else:
    print(ans - 2*absmin)

Submission status: Accepted

Solution code:
N = int(input())
l = list(map(int,input().split()))
l.sort()
s = 0
for i in range(int(len(l)/2)):
  if l[2*i] * l[2*i+1]>0:
  	s += abs(l[2*i] + l[2*i+1])
  else:
    l1 = l[2*i] + l[2*i+1]
    l2 = - l1
    s += l1 if l1>l2 else l2
if(len(l)%2==1):
  s += l[-1]
  
print(s)

Submission status: Accepted

Solution code:
N = int(input())
A = [int(i) for i in input().split()]
B = []
for i in range(N):
    B.append(abs(A[i]))

mini = min(B)
cnt = 0
for i in range(N):
    if A[i] < 0:
        cnt += 1

if cnt % 2 == 0:
    ans = sum(B)
else:
    ans = sum(B) - mini * 2
print(ans)

Submission status: Accepted

Solution code:
N=int(input())
A=list(map(int,input().split()))
m=10000000007
n=0
Ans=0
for i in range(N):
    Ans+=abs(A[i])
    if(A[i]<0):
        n+=1;
    m=min(m,abs(A[i]))
if n%2==0:
    print(Ans)
else:
    print(Ans-2*m)

Submission status: Accepted

Solution code:
_ = input()
A = list(map(int, input().split()))
B = []

minus = 0

for i in A:
    if i < 0:
        minus += 1
    B.append(abs(i))

if minus % 2 == 0:
    print(sum(B))
else:
    print(sum(B) - min(B) * 2)

Submission status: Accepted

Solution code:
n = int(input())
a =  list(map(int, input().split()))

b = []
count = 0
for v in a:
    if v < 0:
        count += 1
        b.append(-v)
    else:
        b.append(v)
if count % 2 == 1:
    b = sorted(b)
    print(sum(b) - 2 * b[0])
else:
    print(sum(b))

Submission status: Accepted

Solution code:
n=int(input())
l=list(map(int,input().split()))
cnt=0
for i in range(n):
    if l[i]<0:
        cnt+=1
        l[i]=abs(l[i])
if cnt%2==0:
    print(sum(l))
else:
    l.sort()
    print(sum(l)-l[0]*2)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

minus = 0
for i in range(n):
    minus += 1 if a[i] < 0 else 0

abs_a = [abs(a[i]) for i in range(n)]

if minus % 2 == 0:
    print(sum(abs_a))
else:
    print(sum(abs_a) - min(abs_a) * 2)

Submission status: Accepted

Solution code:
import numpy as np
import fractions

if __name__ == "__main__":
    N = int(input())
    A = list(map(int, input().split()))
    dp = {}
    dp[0, 0] = 0
    dp[0, 1] = -100000000000
    for i in range(1, N):
        dp[i, 0] = max(dp[i-1,0]+A[i-1], dp[i-1,1]-A[i-1])
        dp[i, 1] = max(dp[i-1,0]-A[i-1], dp[i-1,1]+A[i-1])
    print(max(dp[N-1,0]+A[N-1], dp[N-1,1]-A[N-1]))

Submission status: Accepted

Solution code:
N=int(input())
s=0
m=10**9
pl=0
mi=0

arr=list(map(int,input().split(" ")))

for z in arr:
  s+=abs(z)
  if z>0:
    pl+=1
  elif z<0:
    mi+=1
  if m>abs(z):
    m=abs(z)

if mi%2==0:
  ans=s
else:
  ans=s-2*m
print(ans)

Submission status: Accepted

Solution code:
import sys
# import bisect
# import math
# import itertools
import numpy as np
# import collections
from fractions import Fraction

"""Template"""


class IP:
    """
    入力を取得するクラス
    """

    def __init__(self):
        self.input = sys.stdin.readline

    def I(self):
        """
        1文字の取得に使います
        :return: int
        """
        return int(self.input())

    def S(self):
        """
        1文字の取得(str
        :return: str
        """
        return self.input()

    def IL(self):
        """
        1行を空白で区切りリストにします(int
        :return: リスト
        """
        return list(map(int, self.input().split()))

    def SL(self):
        """
        1行の文字列を空白区切りでリストにします
        :return: リスト
        """
        return list(map(str, self.input().split()))

    def ILS(self, n):
        """
        1列丸々取得します(int
        :param n: 行数
        :return: リスト
        """
        return [int(self.input()) for _ in range(n)]

    def SLS(self, n):
        """
        1列丸々取得します（str
        :param n: 行数
        :return: リスト
        """
        return [self.input() for _ in range(n)]

    def SILS(self, n):
        """
        Some Int LineS
        横に複数、縦にも複数
        :param n: 行数
        :return: list
        """
        return [self.IL() for _ in range(n)]

    def SSLS(self, n):
        """
        Some String LineS
        :param n: 行数
        :return: list
        """
        return [self.SL() for _ in range(n)]


class Idea:
    def __init__(self):
        pass

    def HF(self, p):
        """
        Half enumeration
        半分全列挙です
        pの要素の和の組み合わせを作ります。
        ソート、重複削除行います
        :param p: list : 元となるリスト
        :return: list : 組み合わせられた和のリスト
        """
        return sorted(set(p[i] + p[j] for i in range(len(p)) for j in range(i, len(p))))

    def Bfs2(self, a):
        """
        bit_full_search2
        bit全探索の改良版
        全探索させたら2進数のリストと10進数のリストを返す
        :return: list２つ : １個目 2進数(16桁)  2個目 10進数
        """
        # 参考
        # https://blog.rossywhite.com/2018/08/06/bit-search/
        # https://atcoder.jp/contests/abc105/submissions/4088632
        value = []
        for i in range(1 << len(a)):
            output = []

            for j in range(len(a)):
                if self.bit_o(i, j):
                    """右からj+1番目のiが1かどうか判定"""
                    # output.append(a[j])
                    output.append(a[j])
            value.append([format(i, 'b').zfill(16), sum(output)])

        value.sort(key=lambda x: x[1])
        bin = [value[k][0] for k in range(len(value))]
        val = [value[k][1] for k in range(len(value))]
        return bin, val

    def S(self, s, r=0, m=-1):
        """
        ソート関係行います。色々な設定あります。
        :param s: 元となるリスト
        :param r: reversするかどうか 0=False 1=True
        :param m: （2次元配列）何番目のインデックスのソートなのか
        :return: None
        """
        r = bool(r)
        if m == -1:
            s.sort(reverse=r)
        else:
            s.sort(reverse=r, key=lambda x: x[m])

    def bit_n(self, a, b):
        """
        bit探索で使います。0以上のときにTrue出します
        自然数だからn
        :param a: int
        :param b: int
        :return: bool
        """
        return bool((a >> b & 1) > 0)

    def bit_o(self, a, b):
        """
        bit探索で使います。1のときにTrue出すよ
        oneで1
        :param a: int
        :param b: int
        :return: bool
        """
        return bool(((a >> b) & 1) == 1)

    def ceil(self, x, y):
        """
        Round up
        小数点切り上げ割り算
        :param x: int
        :param y: int
        :return: int
        """
        return -(-x // y)

    def ave(self, a):
        """
        平均を求めます
        :param a: list
        :return: int
        """
        return sum(a) / len(a)

    def gcd(self, x, y):
        if y == 0:
            return x
        else:
            return self.gcd(y, x % y)


"""ここからメインコード"""


def main():
    # 1文字に省略
    r, e, p = range, enumerate, print
    ip = IP()
    id = Idea()
    mod = 10 ** 9 + 7

    """この下から書いてね"""
    n = ip.I()
    a = ip.IL()
    a_abs = np.abs(np.array(a))
    m = np.sign(a)
    o = np.where(m == -1, 1, 0)
    if sum(o) % 2 == 0:
        p(sum(a_abs))
    else:
        a_abs.sort()
        p(sum(a_abs) - (a_abs[0] * 2))



main()

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
B = [abs(a) for a in A]
M = len([a for a in A if a < 0])
if M % 2 == 0:
    print(sum(B))
else:
    print(sum(B) - 2 * min(B))

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

x = 0
z = 0

for i in range(n):
    if a[i]<0:
        x +=1
    if a[i]==0:
        z += 1

b = []
for i in range(n):
    b.append(abs(a[i]))

if z ==0 and x%2 ==1:
    print(sum(b)-min(b)*2)
else:
    print(sum(b))

Submission status: Accepted

Solution code:
N=int(input())
A=list(map(int,input().split()))
m=0
for i in range(N):
  if A[i]<0:
      m+=1
      A[i]=-A[i]
print(sum(A)-(m%2)*2*min(A))

Submission status: Accepted

Solution code:
n = int(input())
a = [int(i) for i in input().split()]
b = 1
absum = 0
m = 10 ** 9
for i in range(n):
    if a[i] < 0:
        b *= (-1)
        absum += (-a[i])
        m = min(m,-a[i])
    else:
        absum += a[i]
        m = min(m,a[i])

if b == -1:
    print(absum -  2 * m)
    #print(absum)
    #print(min(absum))
else:
    print(absum)

Submission status: Accepted

Solution code:
n = int(input())
alist = list(map(int, input().split()))

mina = pow(10, 9) + 7
mc = 0
ans = 0
for a in alist:
  if abs(a) < mina:
    mina = abs(a)
  if a < 0:
    mc += 1
    ans += -a
  else:
    ans += a

if mc % 2 == 0:
  print(ans)
else:
  print(ans - 2 * mina)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
minus = 0
minA = 10**9+1
absSum = 0
for i in range(N):
    minus += A[i]<0
    minA = min(abs(A[i]), minA)
    absSum += abs(A[i])
if(minus%2==1):
    print(absSum-2*minA)
else:
    print(absSum)

Submission status: Accepted

Solution code:
def solve(aaa):
    bbb = list(map(abs, aaa))
    if 0 in aaa:
        return sum(bbb)
    if sum(1 for a in aaa if a < 0) % 2 == 0:
        return sum(bbb)
    return sum(bbb) - 2 * min(bbb)


n = int(input())
aaa = list(map(int, input().split()))
print(solve(aaa))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
s = 0
m = 10**9
n = 0
for x in A:
    if x < 0:
        n += 1
        x = -x
    s += x
    m = min(m, x)
if n%2 == 1:
    s -= 2*m
print(s)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
odd = 0
ans = 0
b = []
for i in range(n):
    b.append(abs(a[i]))
b.sort()
ans = sum(b)
if 0 in a:
    print(ans)
else:
    for i in range(n):
        if a[i] < 0:
            odd += 1
    if odd % 2 == 0:
        print(ans)
    else:
        print(ans - 2*b[0])

Submission status: Accepted

Solution code:
import sys
stdin = sys.stdin
 
sys.setrecursionlimit(10**5) 
 
def li(): return map(int, stdin.readline().split())
def li_(): return map(lambda x: int(x)-1, stdin.readline().split())
def lf(): return map(float, stdin.readline().split())
def ls(): return stdin.readline().split()
def ns(): return stdin.readline().rstrip()
def lc(): return list(ns())
def ni(): return int(stdin.readline())
def nf(): return float(stdin.readline())

n = ni()
a = list(li())

absmin = float('inf')
minusnum = 0
ans = 0
for ai in a:
    absmin = min(absmin, abs(ai))
    
    if ai < 0:
        minusnum += 1
        
    ans += ai if ai > 0 else -ai
        
if minusnum % 2 == 0:
    print(ans)

else:
    print(ans - 2*absmin)

Submission status: Accepted

Solution code:
I=lambda:list(map(int,input().split()))
N=int(input())
A=I()
B=[abs(a)for a in A]
m=sum(1*(a<0)for a in A)%2
if m==0:
    print(sum(B))
else:
    print(sum(B)-min(B)*2)

Submission status: Accepted

Solution code:
N=int(input())
A=[int(i) for i in input().split()]
def CountMinusAndZeroAndMin(lis):#マイナスの個数とabs挿話とabs最小の値を返す
    curmin=1000000000000000
    plussum=0
    minus=0
    for i in lis:
        j=abs(i)
        plussum+=j
        curmin=min(j,curmin)
        if i<0:
           minus+=1
    return(minus,plussum,curmin)
minus,plussum,minabs=CountMinusAndZeroAndMin(A)
if minabs==0 or minus%2==0:
    print(plussum)
else:
    print(plussum-2*minabs)

Submission status: Accepted

Solution code:
from sys import exit

N = int(input())
A = sorted([int(n) for n in input().split()], key=lambda x:abs(x))
# a = [int(input()) for _ in range(N)]
# S = str(input())
# L = len(S)
# T = str(input())
# exit()
minus = False
for i in range(N):
    if(A[i] < 0):
        minus = not minus
        A[i]*=-1
# print(A)
if(minus):
    print(sum(A) - A[0]*2)
else:
    print(sum(A))

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

count_even = 0
for i in range(n//2):
    if a[i*2+1]<=0:
        count_even += 1
count_odd = 0
for i in range((n+1)//2):
    if a[i*2]<=0:
        count_odd += 1
ans = 0
for i in range(n):
    ans += abs(a[i])
if (count_even - count_odd) % 2 == 0:
    print(ans)
else:
    a_abs = [abs(a[i]) for i in range(n)]
    print(ans - min(a_abs)*2)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

cnt = 0
flag = False

for i in range(n):
    if a[i] < 0:
        a[i] = -a[i]
        cnt += 1
    elif a[i] == 0:
        flag = True
    else:
        continue

if flag:
    print(sum(a))
    exit()
    
if cnt % 2 == 0:
    print(sum(a))
else:
    print(sum(a) - 2*min(a))

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

count = 0

for i in range(n):
    if a[i] < 0:
        count += 1
        a[i] = -1*a[i]

if count % 2 == 0:
    print(sum(a))
else:
    print(sum(a)-2*min(a))

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

count = 0
abs_a = []
for i in range(n):
	if a[i] < 0:
		count += 1
		abs_a.append(-a[i])
	else:
		abs_a.append(a[i])

total = sum(abs_a)

if count%2==0:
	print(total)
else:
	smallest = min(abs_a)
	print(total - (2*smallest))

Submission status: Accepted

Solution code:
n = int(input())
nums = list(map(int, input().split()))

total = 0
smallest = 9999999999999999999999999999999
counter = 0
for i in range(n):
    total += abs(nums[i])
    smallest = min(smallest, abs(nums[i]))
    if nums[i] < 0:
        counter += 1

if counter % 2 == 0:
    print(total)
else:
    print(total - 2*smallest)

Submission status: Accepted

Solution code:
N=int(input())
A=[int(x) for x in input().split()]
A.sort()
B=sorted(A,key=lambda x:abs(x))
m=0
for i in range(N):
  if A[i]<0:
    m+=1
  else:
    break
ans=0
for i in range(m):
  ans-=A[i]
for i in range(m,N):
  ans+=A[i]
if m%2==1:
  ans-=abs(B[0])*2
print(ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

num_negative = len(list(filter(lambda e: e < 0, a)))

a2 = [abs(e) for e in a]
if num_negative % 2 == 0:
    print(sum(a2))
else:
    print(sum(a2) - 2 * min(a2))

Submission status: Accepted

Solution code:
from operator import itemgetter
import sys
sys.setrecursionlimit(1000000)
ans=0

n=int(input())
a=[]
b=[]
c=0
for i in input().split():
    x=int(i)
    if x<0:
        c+=1
    a.append(x)
    b.append(abs(x))

b.sort()
ans=sum(b[1:])
if c%2==1:
    ans+=-b[0]
else:
    ans+=b[0]
print(ans)

Submission status: Accepted

Solution code:
N = int(input())
a = list(map(int, input().split()))

sa = 0
min_v = float('inf')
minus_count = 0
for aa in a:
    if aa < 0:
        minus_count += 1
        aa = abs(aa)
    min_v = min(min_v, aa)
    sa += aa

if minus_count % 2 == 0:
    print(sa)
else:
    print(sa - min_v * 2)

Submission status: Accepted

Solution code:
# coding=utf-8

if __name__ == '__main__':
    N = int(input())
    numbers = list(map(int, input().split()))

    minus_count = len([n for n in numbers if n < 0])
    absolute_numbers = [abs(n) for n in numbers]

    if minus_count % 2 == 0:
        print(sum(absolute_numbers))
    else:
        min_num = min(absolute_numbers)
        print(sum(absolute_numbers)-min_num*2)

Submission status: Accepted

Solution code:
N, *A = map(int, open(0).read().split())

p = 0; q = -10**18
for a in A:
    p, q = max(p + a, q - a), max(p - a, q + a)
print(p)

Submission status: Accepted

Solution code:
_,a=open(0);*a,=map(int,a.split());b=[abs(i)for i in a];print(sum(b)-sum(i<0for i in a)%2*min(b)*2)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, list(input().split())))

minus_num = 0

for i in range (n):
    if a[i] <= 0:
        minus_num = minus_num + 1
        a[i] = - a[i]

if minus_num % 2 == 0:
    print(sum(a))
else:
    print(sum(a) - min(a) * 2)

Submission status: Accepted

Solution code:

N=int(input())
a=list(map(int,input().split()))
b=[0]*N
minus=0
ans=0
for i in range(N):
    if a[i]<=0:
        minus+=1
for i in range(N):
    b[i]=abs(a[i])
c=sorted(b)

if minus%2==1:
    for i in range(N-1):
        ans= ans+c[N-i-1]
    ans=ans-c[0]
else:
    for i in range(N):
        ans= ans+c[N-i-1]
print(ans)

Submission status: Accepted

Solution code:
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits

def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N = INT()
A = LIST()

count = 0
for i, x in enumerate(A):
	if x < 0:
		count += 1
		A[i] *= -1
# print(count)
if count % 2 == 0:
	print(sum(A))
else:
	# print(A)
	print(sum(A)-2*min(A))

Submission status: Accepted

Solution code:
import bisect
import numpy as np

N=int(input())

A=list(map(int,input().split()))
A.sort()
minus=bisect.bisect_left(A,0)
Aabs=np.abs(np.array(A))
if minus%2==0 or (minus!=N and A[minus]==0):
  print(np.sum(Aabs))
else:
  Aabs_sort=np.sort(Aabs)
  print(np.sum(Aabs)-(2*Aabs_sort[0]))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))


absmin = abs(A[0])
m = 0
sum = 0

for i in A:
    if i < 0:
        m += 1
    sum += abs(i)
    absmin = min(abs(i),absmin)


if m%2 == 1:
    sum -= absmin*2

print(sum)

Submission status: Accepted

Solution code:
N = int(input())
A = [int(a) for a in input().split()]
DP = [[None, None] for i in range(N)] 
DP[0] = [A[0], -A[0]]
for i in range(1, N):
    DP[i][0] = max(DP[i-1][0] + A[i], DP[i-1][1] - A[i])
    DP[i][1] = max(DP[i-1][0] - A[i], DP[i-1][1] + A[i])
print(DP[N-1][0])

Submission status: Accepted

Solution code:
N = int(input())
A = [x for x in map(int,input().split(" "))]

minus = 0
for i in A:
    if i < 0:
        minus += 1

if minus % 2 == 0:
    print(sum(map(abs,A)))
else:
    b = min(map(abs,A))
    print(sum(map(abs,A))-2*b)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
Am = [n for n in A if n < 0]
if len(Am) % 2 == 0:
    print(sum([abs(n) for n in A]))
else:
    m = min([abs(n) for n in A])
    print(sum([abs(n) for n in A]) - 2 * m)

Submission status: Accepted

Solution code:
N = int(input())
a = list(map(int, input().split()))

minus = 0
for i in range(N):
    if a[i] < 0:
        minus += 1

for i in range(N):
    a[i] = abs(a[i])
if minus % 2 == 0:
    print(sum(a))
else:
    print(sum(a)-2*min(a))

Submission status: Accepted

Solution code:
N = int(input())
A = [int(a) for a in input().split()]
negcnt = 0
mi = 1<<100
s = 0
for a in A:
    s += abs(a)
    mi = min(mi, abs(a))
    if a <= 0:
        negcnt += 1
if negcnt % 2:
    print(s-2*mi)
else:
    print(s)

Submission status: Accepted

Solution code:
N = int(input())
A = [int(i) for i in input().split(" ")]

cnt = 0
zero = False
for i in range(N):
    if A[i] < 0:
        cnt += 1
        A[i] *= -1
    elif A[i] == 0:
        zero = True
if cnt % 2 == 0 or zero:
        print(sum(A))
else:
    print(sum(A) - 2*min(A))

Submission status: Accepted

Solution code:
from heapq import heappush,heappop
import queue
import re
import math
import functools

def int_raw():
    return int(input())

def ss_raw():
    return input().split()

def ints_raw():
    return list(map(int, ss_raw()))

INF = 1<<29

def make1d_arr(n,val=INF):
    return [val for i in range(n)]

def make2d_arr(h,w,val =INF):
    return [[val for i in range(w)]for i in range(h)]


N = int_raw()
A = ints_raw()


def main():
    numNega = len([a for a in A if a<0])
    numZero = len([a for a in A if a==0])
    absA = list(map(abs,A))
    if numZero >1 or numNega%2 == 0:
        return sum(absA)
    else:
        minAbs = min(absA)
        return sum(absA)-minAbs*2

print(main())

Submission status: Accepted

Solution code:
from bisect import bisect_left, bisect_right
from collections import Counter, defaultdict, deque, OrderedDict
from copy import deepcopy
from fractions import gcd
from functools import lru_cache, reduce
from math import ceil, floor
from sys import setrecursionlimit

import heapq
import itertools
import operator


# globals
inf = float('inf')
N = 0
A = []


def set_inputs():
    global N, A
    N = get_int()
    A = get_li()
    return


def main():
    setrecursionlimit(100000)
    set_inputs()
    # ----------MAIN----------
    if 0 in A:
        print(sum(abs(a) for a in A))
    elif len(list(filter(lambda x: x < 0, A))) % 2 == 0:
        print(sum(abs(a) for a in A))
    else:
        m = min(abs(a) for a in A)
        print(sum(abs(a) for a in A) - 2 * m)
    return


def get_int():
    return int(input())


def get_float():
    return float(input())


def get_str():
    return input().strip()


def get_li():
    return [int(i) for i in input().split()]


def get_lf():
    return [float(f) for f in input().split()]


def get_lc():
    return list(input().strip())


def get_data(n, types, sep=None):
    if len(types) == 1:
        return [types[0](input()) for _ in range(n)]
    return list(zip(*(
        [t(x) for t, x in zip(types, input().split(sep=sep))]
        for _ in range(n)
    )))


if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
N = int(input())
*A, = map(int, input().split())

dp = [[0, 0] for i in range(N+1)]
dp[0][1] = -10**18
for i in range(N):
    dp[i+1][0] = max(dp[i][0] + A[i], dp[i][1] - A[i])
    dp[i+1][1] = max(dp[i][0] - A[i], dp[i][1] + A[i])
print(dp[-1][0])

Submission status: Accepted

Solution code:
import math
n=int(input())
a=list(map(int,input().split()))
cnt=0
for i in range(n):
    if a[i]<0:
        a[i]=-a[i]
        cnt+=1
q=min(a)
if cnt%2==0:
    print(sum(a))
else:
    print(sum(a)-2*q)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))

min_a = 10 ** 9
negative_count = 0
ans = 0
for a in A:
    if a < 0:
        negative_count += 1
    a = abs(a)
    ans += a
    if a < min_a:
        min_a = a
if negative_count % 2 == 0:
    print(ans)
else:
    print(ans - 2 * min_a)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))

from functools import reduce

SUM = reduce(lambda x,y: abs(x) + abs(y) , A)

cntMinu = 0
for a in A:
    if a < 0 : cntMinu += 1

if cntMinu % 2 == 0:
    print(SUM)
    exit()

minAbs = 10**9 + 1
for a in A:
    if minAbs > abs(a): minAbs = abs(a)

print(SUM - 2 * minAbs )

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
absMin = float('inf')
absSum = 0
numMinus = 0
for a in A:
  if a < 0:
    numMinus += 1
  ab = abs(a)
  absSum += ab
  absMin = absMin if absMin < ab else ab

if numMinus % 2 == 0:
  print(absSum)
else:
  print(absSum - 2 * absMin)

Submission status: Accepted

Solution code:
n = int(input())
a = [0]+list(map(int, input().split()))+[0]
INF = 1000000000000000000
F = [-INF]*(n+2)
G = [-INF]*(n+2)
F[1] = 0
for i in range(1, n):
	F[i+1] = max(F[i+1], F[i]+a[i], G[i]-a[i])
	G[i+1] = max(G[i+1], F[i]-a[i], G[i]+a[i])
print(max(F[n]+a[n], G[n]-a[n]))

Submission status: Accepted

Solution code:
n,a=int(input()),list(map(int,input().split()))
c,m=0,abs(a[0])
for i in range(n):
  if a[i]<0:c+=1
  m=min(abs(a[i]),m)
ans=0
for i in range(n):ans+=abs(a[i])
if not(m==0 or c%2==0):ans-=m*2
print(ans)

Submission status: Accepted

Solution code:
# coding:utf-8

import sys
# from collections import Counter, defaultdict

INF = float('inf')
MOD = 10 ** 9 + 7

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return input()


def main():
    n = II()
    A = LI()

    minus = 0
    for a in A:
        if a < 0:
            minus += 1

    abs_A = [abs(a) for a in A]
    if minus % 2:
        return sum(abs_A) - min(abs_A) * 2
    else:
        return sum(abs_A)


print(main())

Submission status: Accepted

Solution code:

n = int(input())

An = list(map(int, input().split()))


min_ = 10**9
sum_ = 0
m_count = 0
for a in An:
    if a < 0:
        m_count += 1

    t = abs(a)
    min_ = min(min_, t)
    sum_ += t


#print((min_,sum_,m_count))
ans = sum_ if m_count % 2 == 0 else sum_ - 2*min_

print(ans)

Submission status: Accepted

Solution code:
import sys
input=sys.stdin.readline
n=int(input())
A=list(map(int,input().split()))
B=[]
for a in A:
    B.append(abs(a))
cnt=0
for a in A:
    if a==0:
        cnt=0
    if a<0:
        cnt+=1
print(sum(B)-min(B)*2 if cnt%2 else sum(B))

Submission status: Accepted

Solution code:
#!usr/bin/env python3
from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
def LI(): return list(map(int, sys.stdin.readline().split()))
def I(): return int(sys.stdin.readline())
def LS():return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]
def IR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = I()
    return l
def LIR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = LI()
    return l
def SR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = S()
    return l
def LSR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = LS()
    return l
sys.setrecursionlimit(1000000)
mod = 1000000007

#A
def A():
    a,b,t = LI()
    k = t//a
    print(k*b)
    return

#B
def B():
    n = I()
    v = LI()
    c = LI()
    ans = 0
    for i in range(n):
        if v[i] > c[i]:
            ans += (v[i]-c[i])
    print(ans)
    return

#C
def C():
    def gcd(a,b):
        if a == 0:
            return b
        return gcd(b%a, a)
    n = I()
    a = LI()
    ans = 1
    for i in range(n):
        b = a[:i]+a[i+1:]
        g = b[0]
        for j in range(a):
            print()
    return

#D
def D():
    n = I()
    a = LI()
    k = 0
    for i in a:
        if i < 0:
            k += 1
    ans = 0
    m = float("inf")
    for i in a:
        ans += abs(i)
        m = min(m,abs(i))
    if k%2:
        ans -= 2*m
    print(ans)
    return


#Solve
if __name__ == "__main__":
    D()

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int,input().split()))
absa = list(map(abs,a))
in0 = True if 0 in a else False
if in0:
    ans = sum(absa)
else:
    mc = 0
    for i in a:
        if i < 0:
            mc += 1
    if mc % 2 == 0:
        ans = sum(absa)
    else:
        ans = sum(absa)-2*min(absa)
print(ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int,input().split()))
ans = 0
mn = 10**10
cnt =0
for i in a:
    mn = min(mn,abs(i))
    ans += abs(i)
    if i<0:
        cnt+=1
        cnt%=2
if cnt:
    print(ans-mn*2)
else:
    print(ans)

Submission status: Accepted

Solution code:
import sys
# gcd
# from fractions import gcd
# 切り上げ，切り捨て
# from math import ceil, floor
# リストの真のコピー（変更が伝播しない）
# from copy import deepcopy
# 累積和。list(accumulate(A))としてAの累積和
# from itertools import accumulate
# l = ['a', 'b', 'b', 'c', 'b', 'a', 'c', 'c', 'b', 'c', 'b', 'a']
# S = Counter(l)  # カウンタークラスが作られる。S=Counter({'b': 5, 'c': 4, 'a': 3})
# print(S.most_common(2))  # [('b', 5), ('c', 4)]
# print(S.keys())  # dict_keys(['a', 'b', 'c'])
# print(S.values())  # dict_values([3, 5, 4])
# print(S.items())  # dict_items([('a', 3), ('b', 5), ('c', 4)])
# from collections import Counter
#
# input関係の定義
input = sys.stdin.readline
def ii(): return int(input())
def mi(): return map(int, input().rstrip().split())
def lmi(): return list(map(int, input().rstrip().split()))
def li(): return list(input().rstrip())
# template


N = ii()
A = lmi()
absA = list(map(abs, A))
absA.sort()
cnt = 0

for i in A:
    if i < 0:
        cnt += 1
# print(cnt)
if cnt % 2 == 1:
    print(sum(absA) - 2 * absA[0])
else:
    print(sum(absA))

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
newa = [abs(a[i]) for i in range(n)]

neg = 0
zeros = 0
for i in range(n):
    if a[i] < 0:
        neg += 1 
    elif a[i] == 0:
        zeros += 1 

res = 0 
for i in range(n):
    res += newa[i]
        
if neg%2 == 0:
    print(res)
else:
    if zeros > 0:
        print(res)
    else:
        res -= 2*min(newa)
        print(res)

Submission status: Accepted

Solution code:
n = int(input())
dat = list(map(int,input().split()))

minAbs = 10**10 

s = 0
cntminus = 0
for d in dat:
    if abs(d)<minAbs:
        minAbs = abs(d)
    if d<0:
        cntminus+=1
    s+=abs(d)
if cntminus%2:
    s-=minAbs*2

print(s)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int,input().split()))
ans = 0
minus = 0
q = abs(a[0])
for i in a:
    ans += abs(i)
    q = min(q,abs(i))
    if i < 0:
        minus += 1

if minus%2 == 0:
    print(ans)
else:
    print(ans - 2*q)

Submission status: Accepted

Solution code:
import fractions
def solve():
  n = int(input())
  a = list(int(i) for i in input().split())
  flip = 0
  for i in range(n):
    if a[i] <0:
      a[i] *= -1
      flip += 1
  if flip %2 == 0:
   print(sum(a))
  else:
   print(sum(a)-2*min(a))
solve()

Submission status: Accepted

Solution code:
N=int(input())
B=list(map(int,input().split()))

M=0
for i in range(N):
    if B[i]<0:
        M+=1

C=[]
for i in range(N):
    C.append(abs(B[i]))
C.sort()
if M%2==1:
    print(sum(C)-2*C[0])
else:
    print(sum(C))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))
B = []
nega = 0
for i in A:
    if i < 0:
        B.append(-i)
        nega+=1
    else:
        B.append(i)
if nega % 2 == 1:
    print(sum(B)-2*min(B))
else:
    print(sum(B))