问题提出
设一个正数sum，需将其随机分为n份，其和仍保持为sum。
思路
思考线索如下：
- 先转为正整数问题，浮点数可以转为整数*10^m(m<0) 替换处理。
- 问题转变：假设存在sum个点排为一列，则存在sum-1个间隔。往间隔中插入n-1个分割板，将点分为n份。
- 解决步骤：随机抽取n-1个小于sum的数组成数组，进行顺序排序，并在头部加0，尾部加sum。每个数之间的差(分割板位置)即可得到相加为sum的n份数据。
- 如果为浮点数需要复原。
代码(Python)
```python
# !/usr/env/bin python
# -*- coding: utf-8 -*-
from decimal import Decimal
import random
def split_integer(prototype, part):
if not (isinstance(prototype, int) and isinstance(part, int)):
raise ValueError('Input params should be integer.')
if part <= 1:
raise ValueError('Split part should be more than 1.')
if prototype <= part:
raise ValueError('Split part should be more than split prototype.')
board_set = set()
while len(board_set) < part - 1:
board_set.add(random.randrange(1, prototype))
board_list = list(board_set)
board_list.append(0)
board_list.append(prototype)
board_list.sort()
return [board_list[i + 1] - board_list[i] for i in range(part)]
def split_float(prototype, part):
if not isinstance(prototype, float):
raise ValueError('Input prototype should be float.')
if not isinstance(part, int):
raise ValueError('Input part should be integer.')
prototype = Decimal(str(prototype))
_, decimal_digits, decimal_exponent = prototype.as_tuple()
union_int = Decimal('0')
pow_base = Decimal('10')
for i, d in enumerate(decimal_digits):
union_int += Decimal(str(d)) * pow_base ** (len(decimal_digits) - 1 - i)
return [float(v * pow_base ** decimal_exponent) for v in split_integer(int(union_int), part)]
if __name__ == '__main__':
''' integer sample '''
part = random.randrange(2, 10)
sample_int = random.randrange(20, 100)
print(part, sample_int)
res_int = split_integer(sample_int, part)
print(res_int)
''' float sample '''
part = random.randrange(2, 10)
sample_float = round(random.uniform(20, 100), 8)
print(part, sample_float)
res_float = split_float(sample_float, part)
print(res_float)
```