Problem:
Score : 500 points

Problem Statement

There are N blocks arranged in a row. Let us paint these blocks.

We will consider two ways to paint the blocks different if and only if there is a block painted in different colors in those two ways.

Find the number of ways to paint the blocks under the following conditions:

For each block, use one of the M colors, Color 1 through Color M, to paint it. It is not mandatory to use all the colors.

There may be at most K pairs of adjacent blocks that are painted in the same color.

Since the count may be enormous, print it modulo 998244353.

Constraints

All values in input are integers.

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

0 \leq K \leq N - 1

Input

Input is given from Standard Input in the following format:

N M K

Output

Print the answer.

Sample Input 1

3 2 1

Sample Output 1

6

The following ways to paint the blocks satisfy the conditions: 112, 121, 122, 211, 212, and 221. Here, digits represent the colors of the blocks.

Sample Input 2

100 100 0

Sample Output 2

73074801

Sample Input 3

60522 114575 7559

Sample Output 3

479519525

Solution in Rust (1.42.0) (judge verdict: Accepted)

use proconio::{fastout, input};

const FACT_MAX: usize = 300000;
const MOD: i64 = 998244353;

#[allow(dead_code)]
fn pow_mod(base: i64, power: i64, modulo: i64) -> i64 {
    let mut base = base;
    let mut power = power;
    let mut ans = 1;
    while power > 0 {
        if power & 1 == 1 {
            ans = ans * base % modulo;
        }
        power >>= 1;
        base = base * base % modulo;
    }
    ans
}

thread_local! {
    #[allow(unused)]
    pub static FACT: Vec<i64> = {
        let mut fac: Vec<i64> = vec![1; FACT_MAX+1];

        for i in 1..FACT_MAX+1 {
            fac[i] = (fac[i-1] * i as i64) as i64 % MOD;
        }
        fac
    };

    #[allow(unused)]
    pub static RFACT: Vec<i64> = {
        let mut rfac = vec![1; FACT_MAX+1];
        rfac[FACT_MAX] = FACT.with(|fact| {
            pow_mod(fact[FACT_MAX], MOD-2, MOD)
        });

        for i in (1..FACT_MAX).rev() {
            rfac[i] = (rfac[i+1] * (i+1) as i64) % MOD;
        }
        rfac
    }
}

#[allow(dead_code)]
fn combi(n: usize, m: usize) -> i64 {
    FACT.with(|fact| RFACT.with(|rfact| fact[n] * rfact[n - m] % MOD * rfact[m] % MOD))
}

#[fastout]
fn main() {
    input! {
        (n,m,k): (usize, usize, usize)
    };

    let mut cc = vec![0i64; 3 * 100000];
    cc[1] = m as i64;

    for i in 2..cc.len() {
        cc[i] = cc[i - 1] * ((m - 1) as i64) % MOD;
    }

    let mut ans = 0;

    for i in 0..=k {
        ans += combi(n - 1, n - 1 - i) * cc[n - i];
        ans %= MOD;
    }

    println!("{}", ans);
}