题目描述
Problem Statement
You are given an integer sequence $A = (A_1, A_2, \ldots, A_N)$.
Find the number of pairs of integers (L, R) that satisfy the following conditions:
- $1 \leq L \leq R \leq N$
- There is a number that appears exactly once among $A_L, A_{L + 1}, \ldots, A_R.$ More precisely, there is an integer x such that exactly one integer i satisfies A_i = x and $L \leq i \leq R$.
Input
The input is given from Standard Input in the following format:
N
$A_1 A_2 \ldots A_N$
Output
Print the answer.
Constraints
- $2 \leq N \leq 2 \times 10^5$
- $1 \leq A_i \leq N$
- All input values are integers.
Sample Input 1
5
2 2 1 2 1
Sample Output 1
12
12 pairs of integers satisfy the conditions: (L, R) = (1, 1), (1, 3), (1, 4), (2, 2), (2, 3), (2, 4), (3, 3), (3, 4), (3, 5), (4, 4), (4, 5), (5, 5).
Sample Input 2
4
4 4 4 4
Sample Output 2
4
Sample Input 3
10
1 2 1 4 3 3 3 2 2 4
Sample Output 3
47
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
5
2 2 1 2 1
样例输出
12