3.编写程序，生成包含1000个0到100之间的随机整数，并统计每个元素的出现次数。

import random

# 生成随机整数列表
nums = [random.randint(0, 100) for i in range(1000)]
# 统计元素出现次数
count_dict = {}
for num in nums:
    if num in count_dict:
        count_dict[num] += 1
    else:
        count_dict[num] = 1

# 输出每个元素的出现次数
for num, count in count_dict.items():
    print("{}: {}".format(num, count))