Hello there!

Today we are back with the second article of this series in which we put ChatGPT to the test and without me waffling on any further, lets take a look at the challenge.

Here is the challenge Sum of odd numbers

Followed by the instructions and examples:

Given the triangle of consecutive odd numbers:

             1
          3     5
       7     9    11
   13    15    17    19
21    23    25    27    29
...
Calculate the sum of the numbers in the nth row of this triangle (starting at index 1) e.g.: (Input --> Output)

1 -->  1
2 --> 3 + 5 = 8

Not a great deal to go off of, but simple enough that ChatGPT should not struggle... I think.

Solving it in JavaScript

function rowSumOddNumbers(n) {
     // Calculate the starting number for the nth row
  let start = (n * (n - 1)) + 1;

  // Calculate the sum of the numbers in the nth row
  let sum = 0;

  for (let i = 0; i < n; i++) {
    sum += start + (2 * i);
  }

  return sum;
}

Running the above code makes all tests pass!

Solving it in C

#include <inttypes.h>

uint64_t rowSumOddNumbers(uint32_t n) {
    uint64_t start_num = 1, sum = 0;

    // Calculate the starting number of the nth row
    for (uint32_t i = 1; i < n; i++) {
        start_num += 2 * i;
    }

    // Calculate the sum of the numbers in the nth row
    for (uint32_t i = 0; i < n; i++) {
        sum += start_num + 2 * i;
    }

    return sum;
}

It took 2 attempts for the C implementation to be correct however I think the issue was not starting a new prompt with ChatGPT

Solving it in SQL

SELECT SUM(nums.num) as sum_of_row
FROM 
  (SELECT ((n-1)*(n-1)+1) as num 
   FROM nums WHERE n = [input row number]) as nums
UNION ALL
SELECT SUM(nums.num) as sum_of_row
FROM 
  (SELECT ((n-1)*(n-1)+1) as num 
   FROM nums WHERE n = [input row number]) as nums
  JOIN 
  (SELECT ((n-1)*(n-1)+1) as num 
   FROM nums WHERE n = [input row number]-1) as nums_prev
  ON nums_prev.num < nums.num AND nums_prev.num % 2 = 1

After many attempts, I could not get ChatGPT to understand what it needed to do in order to pass this challenge.

Even before testing the SQL solution I have a feeling it is wrong because it is writing very verbose solutions to what I feel should be quite trivial at this point.

Maybe we will continue with SQL, maybe not. It depends on whether or not I figure out this current challenge!

ChatGPT - Complex Coding Challenges: 7 KYU