POJ-3278 Java版本实现

public class POJ3278 {
private static void main(String[] args){
	final Scanner scanner = new Scanner(System.in);
	int n = scanner.nextInt();
	int k = scanner.nextInt();
	bfs(n, k);

	}
private void bfs(int n, int k){
	if (n >= k) {
	System.out.println(n - k);
	return;
	}
	int[] visits = new int[MAX*2];//0:unvisited 1:visited
	int[] steps = new int[MAX*2];//steps[i] means steps from n to i
	Queue<Integer> integers = new LinkedBlockingQueue<>();
	integers.add(n);
	visited[n] = 1;
	int current;
	intn next = 0;
	while(!integers.isEmpty()) {
		current = integers.poll();
		for(int i = 0; i < 3; i++) {
			if(i == 0) {
				next = current + 1;
				if(next <= MAX && next >= 0 && visit[next] == 0) {
					steps[next] = steps[current] + 1;
					integers.add(next);
					visits[next] = 1;
					if(next == k) {
						System.out.println(steps[next]);
						return;
						}
					}
				} else if(i == 1) {
					next = current - 1;
					if(next <= MAX && next >= 0 && visit[next] == 0) {
					steps[next] = steps[current] + 1;
					integers.add(next);
					visits[next] = 1;
					if(next == k) {
						System.out.println(steps[next]);
						return;
						}
					}
				
					}else {
					next = current * 2;
					if(next <= MAX && next >= 0 && visit[next] == 0) {
					steps[next] = steps[current] + 1;
					integers.add(next);
					visits[next] = 1;
					if(next == k) {
						System.out.println(steps[next]);
						return;
						}
					}
				}
			}
	
		}

	}
}