Problem:
Score : 400 points

Problem Statement

One day, Snuke was given a permutation of length N, a_1, a_2, ..., a_N, from his friend.

Find the following:

Constraints

1 ≦ N ≦ 200,000

(a_1, a_2, ..., a_N) is a permutation of (1, 2, ..., N).

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the answer.

Note that the answer may not fit into a 32-bit integer.

Sample Input 1

3
2 1 3

Sample Output 1

9

Sample Input 2

4
1 3 2 4

Sample Output 2

19

Sample Input 3

8
5 4 8 1 2 6 7 3

Sample Output 3

85

Solution in Kotlin (1.0.0) (judge verdict: Accepted)

import java.util.*

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    val b = IntArray(n)
    for ((i, c) in readLine()!!.split(' ').map(String::toInt).withIndex()) {
        b[c - 1] = i + 1
    }
    val s = TreeSet<Int>()
    s.add(0)
    s.add(n + 1)
    var ans = 0L
    for ((i, p) in b.withIndex()) {
        ans += (s.ceiling(p)!! - p).toLong() * (p - s.floor(p)!!) * (i + 1)
        s.add(p)
    }
    println(ans)
}