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
Constraints:
1 <= nums.length <= 10^5
1 <= nums[i] <= 10^8
1 <= value <= 10^8
At most 50000 calls will be made to showFirstUnique and add.
Solution:
import "container/list"
type FirstUnique struct {
Dict *map[int]int
UQ *list.List
}
func Constructor(nums []int) FirstUnique {
instance := FirstUnique{
Dict: &map[int]int{},
UQ: list.New(),
}
for i := 0; i < len(nums); i++ {
target := (nums)[i]
instance.Add(target)
}
return instance
}
func (this *FirstUnique) ShowFirstUnique() int {
e := (*(this.UQ)).Front()
if e != nil {
return (e.Value).(int)
}
return -1
}
func (this *FirstUnique) Add(value int) {
(*(this.Dict))[value] += 1
switch {
case (*(this.Dict))[value] == 1:
(*(this.UQ)).PushBack(value)
case (*(this.Dict))[value] == 2:
for e := (*(this.UQ)).Front(); e != nil; e = e.Next() {
if (e.Value.(int) == value) {
(*(this.UQ)).Remove(e)
}
}
default:
break;
}
}
/**
* Your FirstUnique object will be instantiated and called as such:
* obj := Constructor(nums);
* param_1 := obj.ShowFirstUnique();
* obj.Add(value);
*/