My code:
public class PhoneDirectory {
boolean[] map;
Queue<Integer> q;
/** Initialize your data structure here
@param maxNumbers - The maximum numbers that can be stored in the phone directory. */
public PhoneDirectory(int maxNumbers) {
map = new boolean[maxNumbers];
q = new LinkedList<Integer>();
for (int i = 0; i < maxNumbers; i++) {
q.offer(i);
}
}
/** Provide a number which is not assigned to anyone.
@return - Return an available number. Return -1 if none is available. */
public int get() {
if (q.isEmpty()) {
return -1;
}
else {
int ret = q.poll();
map[ret] = true;
return ret;
}
}
/** Check if a number is available or not. */
public boolean check(int number) {
return !map[number];
}
/** Recycle or release a number. */
public void release(int number) {
if (map[number]) {
map[number] = false;
q.offer(number);
}
}
}
/**
* Your PhoneDirectory object will be instantiated and called as such:
* PhoneDirectory obj = new PhoneDirectory(maxNumbers);
* int param_1 = obj.get();
* boolean param_2 = obj.check(number);
* obj.release(number);
*/
不是很难，直接拿 Queue做了。
Anyway, Good luck, Richardo! -- 09/11/2016
