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 C++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(){
	int N; 
	cin >> N; 
	int A[200010] = {}; 
	int B[200010] = {}; 
	for(int i = 1; i <= N; i++){
		cin >> A[i]; 
		B[A[i]] = i; 
	}
	vector<int> used = {0, N + 1}; 
	long long int ans = 0; 
	for(int i = 1; i <= N; i++){
		int p = lower_bound(used.begin(), used.end(), B[i]) - used.begin(); 
		ans += (long long) i * (used.at(p) - B[i]) * (B[i] - used.at(p-1)); 
		used.insert(used.begin() + p, B[i]); 
	}
	cout << ans << endl; 
}