README.md

2059. Minimum Operations to Convert Number

You are given a 0-indexed integer array nums containing distinct numbers, an integer start, and an integer goal. There is an integer x that is initially set to start, and you want to perform operations on x such that it is converted to goal. You can perform the following operation repeatedly on the number x:

If 0 <= x <= 1000, then for any index i in the array (0 <= i < nums.length), you can set x to any of the following:

• x + nums[i]
• x - nums[i]
• x ^ nums[i] (bitwise-XOR)

Note that you can use each nums[i] any number of times in any order. Operations that set x to be out of the range 0 <= x <= 1000 are valid, but no more operations can be done afterward.

Return the minimum number of operations needed to convert x = start into goal, and -1 if it is not possible.

Example 1:

Input: nums = [2,4,12], start = 2, goal = 12
Output: 2
Explanation: We can go from 2 → 14 → 12 with the following 2 operations.
- 2 + 12 = 14
- 14 - 2 = 12

Example 2:

Input: nums = [3,5,7], start = 0, goal = -4
Output: 2
Explanation: We can go from 0 → 3 → -4 with the following 2 operations.
- 0 + 3 = 3
- 3 - 7 = -4
Note that the last operation sets x out of the range 0 <= x <= 1000, which is valid.

Example 3:

Input: nums = [2,8,16], start = 0, goal = 1
Output: -1
Explanation: There is no way to convert 0 into 1.

Constraints:

• 1 <= nums.length <= 1000
• -109 <= nums[i], goal <= 109
• 0 <= start <= 1000
• start != goal
• All the integers in nums are distinct.

Solutions (Rust)

1. Solution

use std::collections::VecDeque;

impl Solution {
    pub fn minimum_operations(nums: Vec<i32>, start: i32, goal: i32) -> i32 {
        let mut unvisited = [true; 1001];
        let mut xs = VecDeque::from([(start, 0)]);

        while let Some((x, count)) = xs.pop_front() {
            for &num in &nums {
                let (a, b, c) = (x + num, x - num, x ^ num);

                if a == goal || b == goal || c == goal {
                    return count + 1;
                }

                if a >= 0 && a <= 1000 && unvisited[a as usize] {
                    unvisited[a as usize] = false;
                    xs.push_back((a, count + 1));
                }
                if b >= 0 && b <= 1000 && unvisited[b as usize] {
                    unvisited[b as usize] = false;
                    xs.push_back((b, count + 1));
                }
                if c >= 0 && c <= 1000 && unvisited[c as usize] {
                    unvisited[c as usize] = false;
                    xs.push_back((c, count + 1));
                }
            }
        }

        -1
    }
}