n basamaklı azalmayan sayılar

def count_non_decreasing_opt(n):
    dp = [[0] * 10 for _ in range(n + 1)]
    for i in range(10): dp[1][i] = 1
    for i in range(2, n + 1):
        for j in range(10):
            for k in range(j + 1): dp[i][j] += dp[i - 1][k]
    return sum(dp[n])

def count_non_decreasing_brute(n):
    def solve(n, last):
        if n == 0: return 1
        res = 0
        for i in range(last, 10): res += solve(n - 1, i)
        return res
    return solve(n, 0)