Problem:
Score : 300 points

Problem Statement

Given is a permutation P_1, \ldots, P_N of 1, \ldots, N.
Find the number of integers i (1 \leq i \leq N) that satisfy the following condition:

For any integer j (1 \leq j \leq i), P_i \leq P_j.

Constraints

1 \leq N \leq 2 \times 10^5

P_1, \ldots, P_N is a permutation of 1, \ldots, N.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
P_1 ... P_N

Output

Print the number of integers i that satisfy the condition.

Sample Input 1

5
4 2 5 1 3

Sample Output 1

3

i=1, 2, and 4 satisfy the condition, but i=3 does not - for example, P_i > P_j holds for j = 1.

Similarly, i=5 does not satisfy the condition, either. Thus, there are three integers that satisfy the condition.

Sample Input 2

4
4 3 2 1

Sample Output 2

4

All integers i (1 \leq i \leq N) satisfy the condition.

Sample Input 3

6
1 2 3 4 5 6

Sample Output 3

1

Only i=1 satisfies the condition.

Sample Input 4

8
5 7 4 2 6 8 1 3

Sample Output 4

4

Sample Input 5

1
1

Sample Output 5

1

Solution in Rust (1.15.1) (judge verdict: Runtime Error)


fn main() {
    let n: usize = read();
    let mut p: Vec<usize> = read_vec();
    let mut one = 0;
    for i in &p {
        if *i == 1 {
            one = *i; 
            break;
        }
    }
    let mut run: Vec<usize> = p.into_iter().take(one + 1).collect();
    let mut base = run.clone();
    base.sort();
    let mut ans = 0;
    let mut idx = 1;
    for i in &run {
        if *i == base[idx] {
            idx += 1;
            ans += 1;
        }
    }
    println!("{}", ans);
}

// ========== 以下使い捨て関数  ===============================



// ========== 以下作り置き関数 ================================
use std::io::*;
use std::str::FromStr;

pub const MOD: i64 = 1_000_000_007;

/// 標準入力から
/// 空白文字で囲まれた1つのトークンを
/// 指定の型に変換する
pub fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

/// 標準入力から1行読み取り
/// 空白文字で区切って
/// 指定の型のVecに格納する
pub fn read_vec<T: FromStr>() -> Vec<T> {
    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    s.trim()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}