算法分析与设计第十一周：416. Partition Equal Subset Sum

class Solution(object):
def canPartition(self, nums):
if len(nums) <= 1:
return False

sum1 = sum(nums)
nums.sort()
#若数组中最大值大于数组总和值的一半，则直接返回False
if sum1 % 2 == 1 or nums[-1] > (sum1 >> 1):
return False

def rec(nums, size, val):
if val == 0:
return True
yes = False
#遍历搜索各种可能的组合
for i in range(size - 1, -1, -1):
if nums[i] <= val:
yes |= rec(nums[0:i] + nums[i + 1:], size - 1, val - nums[i])
if yes:
return True

return yes
#因为要将数组分为等值的两部分，所以传入数组总和的一半值
return rec(nums, len(nums), sum1 >> 1)