Solution2.java

class Solution {
    public int minimumOperations(int[] nums, int start, int goal) {
        Deque<Integer> q = new ArrayDeque<>();
        q.offer(start);
        boolean[] vis = new boolean[1001];
        int ans = 0;
        while (!q.isEmpty()) {
            ++ans;
            for (int n = q.size(); n > 0; --n) {
                int x = q.poll();
                for (int y : next(nums, x)) {
                    if (y == goal) {
                        return ans;
                    }
                    if (y >= 0 && y <= 1000 && !vis[y]) {
                        vis[y] = true;
                        q.offer(y);
                    }
                }
            }
        }
        return -1;
    }

    private List<Integer> next(int[] nums, int x) {
        List<Integer> res = new ArrayList<>();
        for (int num : nums) {
            res.add(x + num);
            res.add(x - num);
            res.add(x ^ num);
        }
        return res;
    }
}