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 JavaScript (node.js v5.12) (judge verdict: Time Limit Exceeded)

'use strict';

const lines = require('fs').readFileSync('/dev/stdin', 'utf8').trim().split('\n');
const N = +lines[0];
const A = lines[1].split(' ');

let indices = [];
for (let i = 0; i < N; i++) {
	indices[+A[i] - 1] = i;
}

let sum = 0,
	que = [[0, N - 1, 0]],
	cur = 0;

while (cur < que.length) {
	let lri = que.shift(),
		left = lri[0],
		right = lri[1],
		i = lri[2];
	
	while (indices[i] < left || indices[i] > right) i++;
	let ind = indices[i];
	
	sum += +A[ind] * (ind - left + 1) * (right - ind + 1);
	if (left <= ind - 1) que[que.length] = [left, ind - 1, i + 1];
	if (ind + 1 <= right) que[que.length] = [ind + 1, right, i + 1];
}

console.log(sum);