Python: 判断数组arr中是否有一组数字加起来等于s（动态规划法）

# Recursive method;;
# Codes found at：https://www.youtube.com/watch?v=Jakbj4vaIbE

arr = [3,34,4,12,5,2]

def rec_subset(arr,i,s):
   if s == 0:
       return True
   elif i == 0:
       return arr[0] == s
   elif arr[i] > s:
       return rec_subset(arr,i-1,s)
   else:
       A = rec_subset(arr,i-1,s-arr[i])
       B = rec_subset(arr,i-1,s)
       return A or B
       
print(rec_subset(arr,len(arr)-1,9))

# DP method;
# Codes found at：https://www.youtube.com/watch?v=Jakbj4vaIbE

import numpy as np

arr = [3,34,4,12,5,2]

def dp_subset(arr,S):
   subset = np.zeros((len(arr),S+1),dtype=bool)
   subset[:,0] = True
   subset[0,:] = False
   subset[0,arr[0]] = True
   
   for i in range(1,len(arr)):
       for s in range(1, S+1):
           if arr[i]>s:
               subset[i,s] = subset[i-1,s]
           else:
               A = subset[i-1,s-arr[i]]
               B = subset[i-1,s]
               subset[i,s] = A or B
   
   r,c = subset.shape
   return subset[r-1,c-1]
       
print(dp_subset(arr,9))