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 Rust (1.15.1) (judge verdict: Time Limit Exceeded)

use std::io::{self, Read,Error};
use std::u64;
use std::collections::HashMap;

fn main() {
    let mut buffer = String::new();
    if let Err(e) = io::stdin().read_line(&mut buffer) {
        println!("{}", e);
        return;
    }
    buffer = buffer.trim_right().to_string();

    let mut buffer = String::new();
    // read all values
    if let Err(e) = io::stdin().read_line(&mut buffer) {
        println!("{}", e);
        return;
    }
    let mut vals: Vec<u64> = buffer.split_whitespace().map(|v| v.parse::<u64>().unwrap()).collect();

    let pos_map: HashMap<u64, usize> = vals.iter().enumerate().map(|(i,val)| (val-1,i)).collect();

    let mut sum = 0;
    for val in 0..vals.len() {
        let pos = pos_map[&(val as u64)];
        let val = val as u64;
        // how much it can be expanded to left
        let mut posl = pos;
        while posl > 0 && vals[posl-1] > val {
            posl = posl - 1;
        }
        let mut posr = pos;
        while posr < vals.len() - 1 && vals[posr + 1] > val {
            posr = posr + 1;
        }
        let num_pat = ((pos - posl) + 1) * (posr - pos + 1);
         sum += (val + 1) * num_pat as u64;
    }
    println!("{}", sum);
}