l1 = [6, 4, 2, 1, 5]#未排序
for i in range(1,5):
    print(i)
#第一次循环 i=1 key=4 j=0
#第二次循环 i=2 key=2 j=1
for i in range(1,len(l1)):
    key = l1[i]
    j = i-1
    # l1 [4,6,2,1,5]
    while j>=0 and key<l1[j]:

        l1[j+1] = l1[j]#右移
        # l1 [6,6,4,2,1,5]
        j=j-1
    l1[j+1] = key

print(l1)
l2 = [89,5,6,8,4,12,56,49,7]