[LeetCode] 821. Shortest Distance to a Character_Easy tag: BFS
2018-08-17 10:58 Johnson_强生仔仔 阅读(237) 评论(0) 编辑 收藏 举报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 stringS
.- All letters in
S
andC
are lowercase.
思路为BFS, 类似于[LeetCode] 286. Walls and Gates_Medium tag: BFS.
Code
class Solution(object): def shortestToChar(self, S, C): """ :type S: str :type C: str :rtype: List[int] """ queue, visited, ans, l = collections.deque(), set(), [0]*len(S), len(S) for index, ch in enumerate(S): if ch == C: queue.append((index,0)) visited.add(index) while queue: node, dis = queue.popleft() for d in [-1,1]: n_index = node + d if 0 <= n_index < l and n_index not in visited: ans[n_index] = dis + 1 visited.add(n_index) queue.append((n_index, dis + 1)) return ans