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 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
int main(void){
    int n;
    scanf("%d",&n);
    long long a[n+2],b[n+2],ans=0;
    a[0]=0;
    a[n+1]=0;
    b[n+1]=n+1;
    b[0]=-1;
    for (int i=1; i<=n; i++){
        scanf("%lld",&a[i]);
        b[a[i]]=i;
    }
    for (int i=1; i<=n; i++){
        long long l=1;
        long long r=1;
        while(a[b[i]-l]>i){
            l++;
        }
        while(a[b[i]+r]>i){
            r++;
        }
        ans+=i*l*r;
    }
    printf("%lld\n",ans);
	return 0 ;
}