冒泡排序（easy）

冒泡排序O(n^2)

def buble(n):
    for i in range(n-1):
        for j in range(n-1):
            if lis[j] > lis[j+1]:
                lis[j],lis[j+1] = lis[j+1],lis[j]
lis = [3,2,1]
buble(3)
print(lis)