leetcode 821字符的最短距离

题目：
Given a string S and a character C, return an array of integers representing the shortest distance from the character C in the string.

Example 1:

Input: S = “loveleetcode”, C = ‘e’
Output: [3, 2, 1, 0, 1, 0, 0, 1, 2, 2, 1, 0]

Note:

S string length is in [1, 10000].
C is a single character, and guaranteed to be in string S.
All letters in S and C are lowercase.
题解：
思路：可以用广搜，也可以前后遍历数组来得到最终结果：
n=len(S)
res,pos=
*n,-n
for i in range(n)+range(n)[::-1]:
if S[i]==C:pos=i
res[i]=min(res[i],abs(i-pos))
return res
在python3中应该使用list(range(n))+list(range(n)[::-1])来代替，否则不能正常工作，这是因为在python3中range是使用迭代器来生成数字的