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: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;
int main () {
  int N;
  cin >> N;
  vector<int>A(N);
  vector<int>B(N + 1);
  vector<int>L(N);
  vector<int>R(N);
  for (int i = 0; i < N; i ++) {
    cin >> A[i];
    B[A[i]] = i;
    L[i] = i;
    R[i] = i;
  }
  long long ans = 0;
  for (int i = N; i > 0; i --) {
    int v = B[i];
    long long l = (long long)v - L[i] + 1;
    long long r = (long long)R[i] - v + 1;
    long long j = (long long)i;
    ans += (i * l * r);
    if (v > 0) R[v - 1] = max(R[v - 1], R[v]);
    if (v < N - 1) L[v + 1] = min(L[v + 1], L[v]);
  }
  cout << ans << endl;
}