find the length of the smallest contiguous subarray whose sum is greater than or equal to S

smallest_subarray_sum.py

def smallest_subarray_with_given_sum(s, arr):
  min_ct = float('inf')
  t_head = head_idx = 0
  running_sum = 0
  t_sum = 0
  for tail_idx, num in enumerate(arr):
    running_sum += num
    while running_sum >= s:
      min_ct = min(min_ct, tail_idx - head_idx+1)
      running_sum -= arr[head_idx]
      head_idx += 1
    
  return min_ct


def smallest_subarray_with_given_sum_not_better(s, arr):
  print("max sum={s} and array = {arr}".format(s=s, arr=arr))
  min_ct = float('inf')
  t_head = head_idx = 0
  running_sum = 0
  t_sum = 0
  for tail_idx, num in enumerate(arr):
    running_sum += num
    while running_sum >= s:
      print("head_idx={} tail_idx={}".format(head_idx, tail_idx))
      min_ct = min(min_ct, tail_idx - head_idx+1)
      print("min range is {}".format(min_ct))
      t_head = head_idx
      t_sum = running_sum
      while t_sum >= s and t_sum-arr[t_head] >= s and t_head < tail_idx:
        t_sum -= arr[t_head]
        t_head += 1
        min_ct = min(min_ct, tail_idx - t_head+1)
        print("t_head is {} tail_idx is {} t_sum is {}".format(t_head, tail_idx, t_sum))
        print("min range after adjustment is {}".format(min_ct))
      running_sum -= arr[head_idx]
      head_idx += 1
  print("="*20)  
    
  return min_ct