public class Solution
extends Object
964 - Least Operators to Express Number\.
Hard
Given a single positive integer `x`, we will write an expression of the form `x (op1) x (op2) x (op3) x ...` where each operator `op1`, `op2`, etc. is either addition, subtraction, multiplication, or division (`+`, `-`, `*`, or `/)`. For example, with `x = 3`, we might write `3 * 3 / 3 + 3 - 3` which is a value of 3.
When writing such an expression, we adhere to the following conventions:
* The division operator (`/`) returns rational numbers.
* There are no parentheses placed anywhere.
* We use the usual order of operations: multiplication and division happen before addition and subtraction.
* It is not allowed to use the unary negation operator (`-`). For example, "`x - x`" is a valid expression as it only uses subtraction, but "`-x + x`" is not because it uses negation.
We would like to write an expression with the least number of operators such that the expression equals the given `target`. Return the least number of operators used.
**Example 1:**
**Input:** x = 3, target = 19
**Output:** 5
**Explanation:** 3 \* 3 + 3 \* 3 + 3 / 3.
The expression contains 5 operations.
**Example 2:**
**Input:** x = 5, target = 501
**Output:** 8
**Explanation:** 5 \* 5 \* 5 \* 5 - 5 \* 5 \* 5 + 5 / 5.
The expression contains 8 operations.
**Example 3:**
**Input:** x = 100, target = 100000000
**Output:** 3
**Explanation:** 100 \* 100 \* 100 \* 100. The expression contains 3 operations.
**Constraints:**
* `2 <= x <= 100`
* 1 <= target <= 2 * 108