Difference between := and ← in pseudocode
The use of := in this context appears to be a slip-up from whomever it is who wrote that pseudocode. The initial impression given is that they have different meanings (I thought at first that := was perhaps "redefine", and that ← was "declare and define"). However, with the use of j ← j + 1 on the line following it, it seems clear that the := was a mistake.

In general, := and = are the most common assignment operators, seemingly in both pseudocode and real code. You may be interested in looking at notations of the assignment operator in various programming languages, which include :=, =, &lt;-, ←, and many others.