题目
ou have a queue of integers, you need to retrieve the first unique integer in the queue.
Implement the FirstUnique class:
- FirstUnique(int[] nums) Initializes the object with the numbers in the queue.
- int showFirstUnique() returns the value of the first unique integer of the queue, and returns -1 if there is no such integer.
- void add(int value) insert value to the queue.
解题思路
用所有数建立Counter，从头开始遍历queue，同时维护一个遍历到的位置，如果一个数已经出现过多次，那这个数就再也不会只出现一次
对于add操作，就加入到队列和计数器里
对于showFirstUnique操作，从当前的位置开始遍历，找到第一个出现过第一次的数返回，遍历到队尾还没找到则返回-1
代码
from collections import Counter
class FirstUnique:
def __init__(self, nums: List[int]):
self.ct = Counter(nums)
self.cur = 0
self.nums = nums
def showFirstUnique(self) -> int:
while self.cur < len(self.nums):
if self.ct[self.nums[self.cur]] == 1:
return self.nums[self.cur]
self.cur += 1
return -1
def add(self, value: int) -> None:
self.nums.append(value)
if value not in self.ct:
self.ct[value] = 1
else:
self.ct[value] += 1
# Your FirstUnique object will be instantiated and called as such:
# obj = FirstUnique(nums)
# param_1 = obj.showFirstUnique()
# obj.add(value)
