if pos1 == len(str1) and pos2 == len(str2) and pos3 == len(str3):

return True

if pos3 == len(str3):

return False

return (((pos1 < len(str1) and str1[pos1] == str3[pos3]) and is_interleaved_recursive(str1, str2, str3, pos1 + 1, pos2, pos3 + 1)) or

if len(str3) != (len(str1) + len(str2)):

return False

cols = len(str1) + 1

rows = len(str2) + 1

T = [[False for _ in range(cols)] for _ in range(rows)]

for row in range(rows):

for col in range(cols):

index = row + col - 1

if row == 0 and col == 0:

T[row][col] = True

elif row == 0:

if str3[index] == str1[col - 1]:

T[row][col] = True and T[row][col - 1]

elif col == 0:

if str3[index] == str2[row - 1]:

T[row][col] = True and T[row - 1][col]

else:

T[row][col] = ((T[row][col - 1] if str3[index] == str1[col - 1] else False) or

(T[row - 1][col] if str3[index] == str2[row - 1] else False))