def findZigZagSequence(a, n): a.sort() mid = int((n + 1)/2) - 1 #Used as index, so -1 a[mid], a[n-1] = a[n-1], a[mid]

st = mid + 1
ed = n - 2 #The last element is already in place, thus n-2
while(st <= ed):
    a[st], a[ed] = a[ed], a[st]
    st = st + 1
    ed = ed - 1 #Decreasing

for i in range (n):
    if i == n-1:
        print(a[i])
    else:
        print(a[i], end = ' ')
return

test_cases = int(input()) for cs in range (test_cases): n = int(input()) a = list(map(int, input().split())) findZigZagSequence(a, n) Sorting the Array:

The input array a is sorted to ensure it starts in ascending order. This is crucial for constructing the lexicographically smallest zig-zag sequence. Finding and Swapping the Middle Element:

The middle index is calculated as (n + 1) / 2 - 1, adjusted to match Python's 0-based indexing. The middle element is swapped with the last element of the array to start forming the zig-zag pattern. Reversing the Second Half:

From the element right after the middle (st = mid + 1) to the second last element (ed = n - 2), elements are swapped iteratively to reverse this section of the array. This ensures the second half is in decreasing order. Output the Result:

The final zig-zag sequence is printed. The code ensures the last element ends with a newline, while others are separated by spaces. Test Case Loop:

The program handles multiple test cases by iterating over the input and applying the transformation for each array. Key Points: Zig-Zag Definition: The first half of the array is in increasing order, and the second half is in decreasing order. Efficiency: Sorting is O(n log n), and reversing the second half is O(n), making the solution efficient. Lexicographical Order: Sorting ensures the sequence remains lexicographically smallest. This approach ensures the requirements of the problem are met concisely and effectively.

Only change 3 lines but doesn't provide all languages. So if you make a new solution from scratch, your solution always fails due to creating more than 3 lines of code.

Python 3 (comments on changed lines)

def findZigZagSequence(a, n):
    a.sort()
    mid = int((n + 1)/2) - 1 #Used as index, so -1
    a[mid], a[n-1] = a[n-1], a[mid]

    st = mid + 1
    ed = n - 2 #The last element is already in place, thus n-2
    while(st <= ed):
        a[st], a[ed] = a[ed], a[st]
        st = st + 1
        ed = ed - 1 #Decreasing

    for i in range (n):
        if i == n-1:
            print(a[i])
        else:
            print(a[i], end = ' ')
    return

test_cases = int(input())
for cs in range (test_cases):
    n = int(input())
    a = list(map(int, input().split()))
    findZigZagSequence(a, n)

i have made my solution in c and it's workig with the exact output when debuging on codeblocks but when submitting it on the site it gives me wrong answer

Although the expected output is matching with my output it's not passing. def findZigZagSequence(a, n): a.sort()#Sorting the array mid = int(n/2)#Finding the middle element a[mid], a[n-1] = a[n-1], a[mid] #Swapping the middle element with the max number #print(a) st = mid + 1 ed = n - 2 while(st <= ed): a[st], a[ed] = a[ed], a[st] st = st + 1 ed = ed - 1

for i in range (n):
    if i == n-1:
        print(a[i])
    else:
        print(a[i], end = ' ')
return

test_cases = int(input()) for cs in range (test_cases): n = int(input()) a = list(map(int, input().split())) findZigZagSequence(a, n)