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# (Mono 4.6.2.0) (judge verdict: Time Limit Exceeded)

using System;
using System.Collections.Generic;
using System.Linq;

namespace AGC005_B
{
    class Program
    {
        static int N;
        static long ans;
        static void Main(string[] args)
        {
            N = scan[0];
            var A = scan;

            //区間は NC2 （始点と終点を選ぶ）
            var B = new int[N + 1];
            for (int i = 1; i <= N; i++)
            {
                B[A[i - 1]] = i;
            }

            //C#のSetにはLowerBoundがないけども
            var G = new SortedSet<int>();
            for (int i = 1; i <= N; i++)
            {
                G.Add(B[i]);
                var D = G.ToArray();
                var d = LowerBound(D, B[i]);
                int l = (d == 0) ? D[d] : D[d] - D[d - 1];
                int r = (d == i - 1) ? N -  D[d] + 1 : D[d + 1] - D[d];
                ans += (long)l * r * i;
                //Console.WriteLine(d+" " +l+" "+r+" "+ans);

            }
            Console.WriteLine(ans);

        }

        static int LowerBound(int[] arr, int val)
        {
            int low = 0, high = arr.Count();
            int mid;

            while (low < high)
            {
                mid = ((high - low) >> 1) + low;
                if (arr[mid] < val) low = mid + 1;
                else high = mid;
            }
            return low;
        }
        static int[] scan { get { return Array.ConvertAll(Console.ReadLine().Split(), int.Parse); } }
    }
}