Array.Exists - Possible bug?

Question

I was recently trying to complete a pretty good LeetCode exercise, and I can say that the solution I'm trying to use is not the best, but it's still been good practice. However, I noticed when using the Array.Exists function, I don't get consistent results as I'd expect when debugging with Console.WriteLine. Granted, I'm using this on a jagged array, but I would THINK that this would work, iterating on an array line by line. Considering the following example 2D array:

[[0,1],[0,1],[0,1]]

Given this array, you would THINK that when iterating through the array, you would be able to use Array.Exists to find that there IS, indeed, a 1 AND a 0 each subsequent sub-array, like when running these lines:

Console.WriteLine(Array.Exists<int>(grid[i], x => x.Equals(0)));
Console.WriteLine(Array.Exists<int>(grid[i], x => x.Equals(1)));

I would expect to return the following while looping through the array with i and j iterators:

True
True

However, when moving from the FIRST sub-array (grid[0] onto grid[1], for example), I would get false negatives, as if there was indeed no 1 in the array, which we know is false:

True
False

These should both be true in this jagged array, but apparently it's not, at least on the LeetCode website.

Is anyone else able to replicate this?

Here's a small program that shows the issue I'm talking about when run in a console application:

using System;

public class Solution {

    public static void Main(String[] args) {

        int[][] exampleGrid = new int[][]
        {
            new int[] {2,0},
            new int[] {1,0}
        };

        Solution.Feedback(exampleGrid);

    }

    public static void Feedback(int[][] grid) {
          for(int i = 0; i < grid.GetLength(0); i++)
          {
              Console.WriteLine(Array.Exists<int>(grid[i], x => x.Equals(0)));
              Console.WriteLine(Array.Exists<int>(grid[i], x => x.Equals(1)));
           }
  }
}

Please note: this only appears to be reproducible in mono 5.18.0 - C# 7.

Answer 1

I can confirm it's definitely not a compiler bug of any sort, but the code itself. I was unable to replicate on Leetcode itself on their playground.

And then I discovered it was definitely a bug of my own. Go figure!

For those that wish to find my bug, give any input, or something different otherwise, feel free to go here:

https://leetcode.com/playground/PSz4zMzL

But this is not the scope of this post anymore - so I'll just move along.