Zig Zag Sequence

Problem Statement :

In this challenge, the task is to debug the existing code to successfully execute all provided test files.

Given an array of n distinct integers, transform the array into a zig zag sequence by permuting the array elements. A sequence will be called a zig zag sequence if the first k elements in the sequence are in increasing order and the last k elements are in decreasing order, where k = ( n+1) /2 . You need to find the lexicographically smallest zig zag sequence of the given array.

Note: You can modify at most three lines in the given code. You cannot add or remove lines of code.

To restore the original code, click on the icon to the right of the language selector.

Input Format

The first line contains t the number of test cases. The first line of each test case contains an integer n, denoting the number of array elements. The next line of the test case contains n elements of array a.


1   <=   t  <=  20
1  <=  n  <=   10000 ( n  is always odd)
1   <=   ai  <=  10^9

Output Format

For each test cases, print the elements of the transformed zig zag sequence in a single line.

Solution :


                            Solution in C :

In   Python3  :

def findZigZagSequence(a, n):
    mid = int((n + 1)/2)-1#1st change
    a[mid], a[n-1] = a[n-1], a[mid]

    st = mid + 1
    ed = n - 2#2nd change
    while(st <= ed):
        a[st], a[ed] = a[ed], a[st]
        st = st + 1
        ed = ed - 1 #3rd change

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

In    Java  :

// first change
   int mid = (n+1)/2 - 1;

// second change
  int ed = n - 2;

//third change
  ed = ed - 1;

View More Similar Problems

The Strange Function

One of the most important skills a programmer needs to learn early on is the ability to pose a problem in an abstract way. This skill is important not just for researchers but also in applied fields like software engineering and web development. You are able to solve most of a problem, except for one last subproblem, which you have posed in an abstract way as follows: Given an array consisting

View Solution →

Self-Driving Bus

Treeland is a country with n cities and n - 1 roads. There is exactly one path between any two cities. The ruler of Treeland wants to implement a self-driving bus system and asks tree-loving Alex to plan the bus routes. Alex decides that each route must contain a subset of connected cities; a subset of cities is connected if the following two conditions are true: There is a path between ever

View Solution →

Unique Colors

You are given an unrooted tree of n nodes numbered from 1 to n . Each node i has a color, ci. Let d( i , j ) be the number of different colors in the path between node i and node j. For each node i, calculate the value of sum, defined as follows: Your task is to print the value of sumi for each node 1 <= i <= n. Input Format The first line contains a single integer, n, denoti

View Solution →

Fibonacci Numbers Tree

Shashank loves trees and math. He has a rooted tree, T , consisting of N nodes uniquely labeled with integers in the inclusive range [1 , N ]. The node labeled as 1 is the root node of tree , and each node in is associated with some positive integer value (all values are initially ). Let's define Fk as the Kth Fibonacci number. Shashank wants to perform 22 types of operations over his tree, T

View Solution →

Pair Sums

Given an array, we define its value to be the value obtained by following these instructions: Write down all pairs of numbers from this array. Compute the product of each pair. Find the sum of all the products. For example, for a given array, for a given array [7,2 ,-1 ,2 ] Note that ( 7 , 2 ) is listed twice, one for each occurrence of 2. Given an array of integers, find the largest v

View Solution →

Lazy White Falcon

White Falcon just solved the data structure problem below using heavy-light decomposition. Can you help her find a new solution that doesn't require implementing any fancy techniques? There are 2 types of query operations that can be performed on a tree: 1 u x: Assign x as the value of node u. 2 u v: Print the sum of the node values in the unique path from node u to node v. Given a tree wi

View Solution →