DATA STRUCTURES PROGRAM • QUEUES & DEQUES

Interleave the Two Halves of a Queue

Learn how to interleave the two halves of a queue using a clear C program.

IntermediateQueueFIFOfront/rear

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

1 4 2 5 3 6

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int queue[] = {1, 2, 3, 4, 5, 6};
    int first_half[] = {1, 2, 3};
    for (int index = 0; index < 3; index++) {
        printf("%d %d ", first_half[index], queue[index + 3]);
    }
    putchar('\n');
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

1 4 2 5 3 6

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Separate the first half, then alternately take one value from each half.
Display the computed result.

Separate the first half, then alternately take one value from each half.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(n)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.