[python] 帕斯卡三角

                                帕斯卡三角是法国数学家帕斯卡（1623—1662）发现的。中国南宋时期的杨辉也发现了它并且比西方的数学家早，在中国也叫杨辉三角。
def pascal():
  row = [1]
  while True:
    yield row
    this = [0] + row
    next = row + [0]
    row = [a+b for a,b in zip(this, next)]
gen=pascal()
for i in range(10):
  print gen.next()
-----------------------------------------------
[1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]
[1, 5, 10, 10, 5, 1]
[1, 6, 15, 20, 15, 6, 1]
[1, 7, 21, 35, 35, 21, 7, 1]
[1, 8, 28, 56, 70, 56, 28, 8, 1]
[1, 9, 36, 84, 126, 126, 84, 36, 9, 1]