如何构建具有非负值的随机游走？

import random

def non_negative_random_walk(steps):
    position = 0
    for _ in range(steps):
        move = random.choice([-1, 1])
        position += move
        if position < 0:
            position = -position
    return position

import random

def non_negative_random_walk(steps):
    position = 0
    for _ in range(steps):
        move = random.choice([-1, 1])
        position += move
        if position < 0:
            position = 0
    return position

import random
import numpy as np

def non_negative_random_walk(steps):
    position = 0
    for _ in range(steps):
        move = np.random.exponential(scale=1)  # 使用指数分布
        position += move
    return position