Subsequence Vs Substring Vs Subarray

Substring 👍

A substring is a contiguous(continuous) sequence of characters present within a string. It is a string present inside a string.
For instance, the substrings of the string “tree” would be:
‘t,’ ‘r,’ ‘e,’ ‘tr,’ ‘tre,’ ‘tree,’ ‘re,’ ‘ree,’ ‘ee’ and ‘’

• We can use single ‘ ’ or double “ ” quotes to denote substring.

• The entire string is a substring of itself.

• An empty string is also a substring of the given string.

Sub-array 👍
We all know that an array is a contiguous memory block.
So a subarray is a contiguous sequence of elements within an array. An empty array is also a subarray of an array.

Arrays can be denoted by curly brackets {} or square brackets [].

The example below gives a clear view of the subarrays of an array:
int array[ ] = {1, 5, 4};
Therefore, subarrays for the array {1,5,4} are {1}, {1,5}, {1,5,4}, {5}, {5,4}, {4} and {}

Sequence 👍
A Sequence can be thought of as a list of elements with a particular order.

For example, [A, B, C, D, E, F] is a sequence or [1,4,3,2,1,5] => While the elements in this sequence are of different types (numbers and letters), they are presented in a specific order, separated by commas, which makes it a sequence.

Subsequence 👍

A subsequence is a sequence that can be derived from another sequence of elements without changing the order of the remaining elements.

For example: {A, B, D} is one of the subsequences of the sequence {A, B, C, D, E} obtained after removing {C} and {E}.
Parties: Subsequence and Longest Common Subsequence (LCS) https://www.youtube.com/watch?v=VbcDFmHkuoA