Watch 10 video solutions for Least Operators to Express Number, a hard level problem involving Math, Dynamic Programming, Memoization. This walkthrough by CrioDo has 304,611 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
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:
/) returns rational numbers.-). 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 <= 1001 <= target <= 2 * 108