1429. First Unique Number 返回第一个独特的数字
作者:互联网
You 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.
Example 1:
Input: ["FirstUnique","showFirstUnique","add","showFirstUnique","add","showFirstUnique","add","showFirstUnique"] [[[2,3,5]],[],[5],[],[2],[],[3],[]] Output: [null,2,null,2,null,3,null,-1] Explanation: FirstUnique firstUnique = new FirstUnique([2,3,5]); firstUnique.showFirstUnique(); // return 2 firstUnique.add(5); // the queue is now [2,3,5,5] firstUnique.showFirstUnique(); // return 2 firstUnique.add(2); // the queue is now [2,3,5,5,2] firstUnique.showFirstUnique(); // return 3 firstUnique.add(3); // the queue is now [2,3,5,5,2,3] firstUnique.showFirstUnique(); // return -1
Example 2:
Input: ["FirstUnique","showFirstUnique","add","add","add","add","add","showFirstUnique"] [[[7,7,7,7,7,7]],[],[7],[3],[3],[7],[17],[]] Output: [null,-1,null,null,null,null,null,17] Explanation: FirstUnique firstUnique = new FirstUnique([7,7,7,7,7,7]); firstUnique.showFirstUnique(); // return -1 firstUnique.add(7); // the queue is now [7,7,7,7,7,7,7] firstUnique.add(3); // the queue is now [7,7,7,7,7,7,7,3] firstUnique.add(3); // the queue is now [7,7,7,7,7,7,7,3,3] firstUnique.add(7); // the queue is now [7,7,7,7,7,7,7,3,3,7] firstUnique.add(17); // the queue is now [7,7,7,7,7,7,7,3,3,7,17] firstUnique.showFirstUnique(); // return 17
Example 3:
Input: ["FirstUnique","showFirstUnique","add","showFirstUnique"] [[[809]],[],[809],[]] Output: [null,809,null,-1] Explanation: FirstUnique firstUnique = new FirstUnique([809]); firstUnique.showFirstUnique(); // return 809 firstUnique.add(809); // the queue is now [809,809] firstUnique.showFirstUnique(); // return -1
基础知识没学好,不解释。已经补上了
https://leetcode.com/problems/first-unique-number/discuss/601107/JavaPython-3-DoublyLinkedList-and-LinkedHashSetdict-O(n)-2-neat-codes-w-analysis.
private Set<Integer> unique = new LinkedHashSet<>(); private Set<Integer> total = new HashSet<>(); public FirstUnique(int[] nums) { for (int n : nums) { add(n); } } public int showFirstUnique() { /* for (int v : unique) { return v; } return -1; */ return unique.isEmpty() ? -1 : unique.iterator().next(); // credit to @yelhsabananah } public void add(int value) { if (total.add(value)) { unique.add(value); }else { unique.remove(value); } }
标签:null,1429,Number,queue,FirstUnique,add,showFirstUnique,firstUnique,Unique 来源: https://www.cnblogs.com/immiao0319/p/15201818.html