Expression Add Operators

Problem Given a string of digits and a target value, insert the binary operators +, -, and * between digits (multi-digit operands allowed, but no leading zeros) so the resulting expression evaluates to the target. Return all such expressions.

Input / Output

• Input: digit string num, integer target.
• Output: all valid operator insertions as strings.

Constraints

• 1 ≤ |num| ≤ 10.
• Operands may span multiple digits but must not have a leading zero.

Example

• num = "123", target = 6 → ["1+2+3","123"]; num = "232", target = 8 → ["23+2","2+32"].