n_sum = 0

def solve():
    n = int(input())
    a = list(map(int, input().split()))

    assert 3 <= n <= 2 * 10 ** 5
    assert all(-10**9 <= x <= 10**9 for x in a)
    global n_sum
    n_sum += n
    assert n_sum <= 5 * 10 ** 5
    
    inf = 10**18
    dp = [[[-inf] * (n + 1) for _ in range(3)] for _ in range(2)]
    dp[0][0][0] = 0
    dp[0][0][1] = 0
    for i, x in enumerate(a):
        for j in range(3):
            dp[0][j][i + 1] = dp[0][j][i] + x
            dp[1][j][i + 1] = dp[1][j][i] - x
        if i > 0:
            for j in range(2):
                dp[0][j + 1][i + 1] = max(dp[0][j + 1][i + 1], dp[0][j][i] + x, dp[1][j][i] + x)
                dp[1][j + 1][i + 1] = max(dp[1][j + 1][i + 1], dp[0][j][i] - x, dp[1][j][i] - x)
    ans = max(dp[0][2][n], dp[1][2][n])
    print(ans)

t = int(input())
assert 1 <= t <= 10 ** 5
for _ in range(t):
    solve()